MAGNETOCALORIC MATERIALS COMPRISING MANGANESE, IRON, SILICON, PHOSPHORUS AND NITROGEN

Abstract

The present invention relates to magnetocaloric materials comprising manganese, iron, silicon, phosphorus, nitrogen and optionally boron.

Claims

1. A magnetocaloric material having a composition according to the general formula (I):
(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.vN.sub.zB.sub.w(I), wherein: 0.1u0.11; 0.2x0.8, 0.3y0.75; 0.25v0.7; 0w0.1; 0.001z0.11; y+v+w<1; and y+v+z+w>1.

2. The magnetocaloric material according to claim 1, wherein: the magnetocaloric material exhibits a hexagonal crystalline structure of the Fe.sub.2P type with a crystal lattice having the space group P-62m; nitrogen atoms occupy crystal sites, interstitial sites of said crystal lattice, or both; and boron atoms if present occupy crystal sites of said crystal lattice according to the hexagonal crystal system with the space group P-62m.

3. The magnetocaloric material according to claim 2, wherein nitrogen atoms occupy at least one of: crystal sites of said crystal lattice having the space group P-62m, and interstitial sites of said crystal lattice having the space group P-62m.

4. The magnetocaloric material according to claim 1, wherein: the magnetocaloric material has a composition according to the general formula (I):
(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.vN.sub.zB.sub.w(I); 0.05u0.05; 0.3x0.7; 0.4y0.7; 0.3v0.61; 0.04w0.08; 0.005z0.07; y+v+w<1; and y+v+z+w1.

5. The magnetocaloric material according to claim 1, wherein: the magnetocaloric material has a composition according to the general formula (II):
(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.vN.sub.z(II); 0.1u0.1; 0.2x0.8; 0.3y0.75; 0.25v0.7; 0.001z0.1; y+v1; y+v+z1; and 0.001z0.1.

6. The magnetocaloric material according to claim 1, wherein: the magnetocaloric material has a composition according to the general formula (III):
(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.1yN.sub.z(III); 0.1u0.1; 0.2x0.8; 0.3y0.75; and 0.001z0.1.

7. The magnetocaloric material according to claim 1, wherein: the magnetocaloric material has a composition according to the general formula (IV):
(Mn.sub.xFe.sub.11).sub.2+uP.sub.ySi.sub.1yzN.sub.z(IV); 0.1u0.1; 0.2x0.8; 0.3y0.75; 0.001z0.1; and.

8. The magnetocaloric material according to claim 1, which is selected from the group consisting of Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.01, Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.03, Mn.sub.1.25Fe.sub.0.7P.sub.0.49Si.sub.0.5N.sub.0.01, Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.49N.sub.0.01, Mn.sub.1.25Fe.sub.0.7P.sub.0.5 Si.sub.0.5N.sub.0.05, Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.07, Mn.sub.1.25Fe.sub.0.7P.sub.0.47Si.sub.0.5N.sub.0.03, Mn.sub.1.25Fe.sub.0.7P.sub.0.43Si.sub.0.5N.sub.0.07, MnFe.sub.0.95P.sub.0.45Si.sub.0.55N.sub.0.02, MnFe.sub.0.95P.sub.0.44Si.sub.0.50B.sub.0.06N.sub.0.02, and Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53N.sub.0.01.

9. A process for producing the magnetocaloric material according to claim 1, the process comprising: (a) reacting a mixture of precursors in the solid phase, liquid phase, or both, to obtain a solid or liquid reaction product, and if the reaction product is a liquid reaction product, transferring the liquid reaction product into the solid phase to obtain the solid reaction product; (b) optionally shaping the solid reaction product to obtain a shaped solid reaction product; (c) heat treating the solid reaction product or the shaped solid reaction product to obtain a heat treated product; (d) cooling the heat treated product to obtain a cooled product; and (e) optionally shaping of the cooled product, ob wherein: the mixture of precursors comprises atoms the elements manganese, iron, silicon, phosphorus, nitrogen, and optionally boron; and a stoichiometric ratio of total amounts of the atoms of the elements corresponds to a stoichiometric ratio of the atoms of the elements in the magnetocaloric material.

10. The process according to claim 9, wherein the mixture of precursors further comprises at least one selected from the group consisting of elemental manganese, elemental iron, elemental silicon, elemental phosphorus, elemental boron, a nitride of iron, a boride of iron, a boride of manganese, a phosphide of iron, a phosphide of manganese, ammonia gas and nitrogen gas.

11. The process according to claim 9, wherein the reacting of the mixture of precursors comprises reacting the mixture of precursors in the solid phase by ball-milling so that a reaction product in the form of a powder is obtained.

12. The process according to claim 9, wherein the reacting of the mixture of precursors comprises reacting the mixture of precursors in the liquid phase and transferring the obtained liquid reaction product into the solid phase by quenching, melt-spinning or atomization.

13. The process according to claim 9, wherein the heat treating comprises sintering the solid reaction product or the shaped solid reaction product.

14. (canceled)

15. A device, comprising at least one magnetocaloric material of claim 1, wherein the device is selected from the group consisting of a cooling system, a heat exchanger, a heat pump, a thermomagnetic generator and a thermomagnetic switch.

Description

EXAMPLES

Preparation of Magnetocaloric Materials

Step (a)

[0123] For the preparation of the magnetocaloric materials according to the present invention listed in table 1, in each case 15 g of a mixture consisting of the precursors elemental manganese, elemental iron, iron nitride (nominal composition approximately Fe.sub.3N), elemental red phosphorus, elemental silicon and optionally elemental boron (each in the form of a powder) in the amounts (in gram) given in table 1 was provided. For the preparation of comparison materials not according to the present invention, a mixture consisting of the precursors elemental manganese, elemental iron, elemental red phosphorus and elemental silicon (each in the form of a powder) was provided as indicated in table 1.

[0124] In the precursor mixtures, the proportions of the precursors are adjusted so that the stoichiometric ratio of the total amounts of atoms of iron, manganese, phosphorus, silicon, nitrogen (if present) and boron (if present) corresponds to the stoichiometric ratio of the atoms of iron, manganese, phosphorus, silicon, nitrogen (if present) and boron (if present) in the magnetocaloric material to be produced (formula in the column composition in table 1).

Step (b)

[0125] Magnetocaloric materials according to the present invention were prepared by reacting the mixtures provided in step (a) in the solid phase using a planetary ball mill (Fritsch Pulverisette) with four grinding bowl fasteners. Each grinding bowl (80 ml volume) contains seven balls (10 mm diameter) made of tungsten carbide and 15 grams of a mixture of precursors prepared in step (a). The mixtures were ball milled for 10 hours with a constant rotation speed of 380 rpm in an argon atmosphere. (The total time in the ball mill is 16.5 hours, the machine stops milling for 10 minutes after every 15 minutes of milling).

Step (c)

[0126] After ball-milling the obtained reaction product which is in the form or a powder was compacted to small tablets (diameter 12 mm, height 5-10 mm) in a hydraulic pressing system with a pressure of 1.47 kPa (150 kgf cm.sup.2).

Step (d)

[0127] After pressing, the tablets were sealed inside quartz ampoules in an argon atmosphere of 20 kPa (200 mbar). Then, the samples were sintered at 1100 C. for 2 h and annealed at 850 C. for 20 h and then cooled down slowly to room temperature by turning off the oven (known to the specialist as oven cooling) before re-sintering at 1100 C. for 20 h to achieve a homogeneous composition.

Step (e)

[0128] The thermal treatment of step (d) was finished by contacting the ampoules with water.

[0129] The composition of magnetocaloric materials prepared in the above-described manner and the composition of the corresponding precursor mixtures is given in table 1 below:

TABLE-US-00001 TABLE 1 Iron nitride Composition Mn/[g] Fe/[g] Fe.sub.2-4N/[g] P/[g] Si/[g] B/[g] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5 7.5022 4.2712 0.0000 1.6916 1.5430 0.0000 (comparison example) Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.01 7.4952 4.1026 0.1793 1.6907 1.5329 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.03 7.4795 3.7655 0.5386 1.6851 1.5296 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.05 7.4648 3.4296 0.8963 1.6830 1.5266 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.07 7.4496 3.0959 1.2534 1.6800 1.5230 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.49Si.sub.0.5N.sub.0.01 7.5127 4.1116 0.1810 1.6604 1.5362 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.47Si.sub.0.5N.sub.0.03 7.5309 3.7907 0.5425 1.5963 1.5399 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.43Si.sub.0.5N.sub.0.07 7.5685 3.1455 1.2709 1.4680 1.5477 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.49N.sub.0.01 7.5107 4.1110 0.1809 1.6932 1.5053 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.47N.sub.0.03 7.5256 3.7890 0.5418 1.6976 1.4465 0.0000 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.45N.sub.0.05 7.5413 3.4659 0.9048 1.7007 1.3876 0.0000 MnFe.sub.0.95P.sub.0.45Si.sub.0.55N.sub.0.02 5.9865 5.4528 0.3591 1.5186 1.6833 0.0000 MnFe.sub.0.95P.sub.0.44Si.sub.0.5B.sub.0.06N.sub.0.02 6.0332 5.4950 0.3616 1.4966 1.5422 0.0714 Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53 7.6037 4.1360 0.0000 1.6118 1.6484 0.0000 (comparison example) Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53N.sub.0.01 7.4998 4.0795 0.2051 1.5898 1.6259 0.0000

Sample Preparation and Characterization of Magnetocaloric Materials

[0130] The magnetocaloric materials prepared as described above were cooled in liquid nitrogen to remove the virgin effect. Then the magnetocaloric materials were manually crushed by means of a mortar to prepare powders for the measurements. Most interestingly, pristine magnetocaloric materials according to the present invention remain in their physical form when cooled in liquid nitrogen compared to pristine magnetocaloric materials consisting of iron, manganese, silicon and phosphorus (i.e. not containing nitrogen) that are easily fragmented. In other words, the presence of nitrogen appears to provide for improved mechanical stability of magnetocaloric materials comprising iron, manganese, silicon and phosphorus.

[0131] The crystalline structure of all samples was characterized by X-ray power diffraction using a PANalytical X-pert Pro diffractometer with CuK.sub. radiation. The refinements have been done using the Fullprof program.

[0132] A differential scanning calorimeter (DSC) equipped with a liquid nitrogen cooling system was used to measure the specific heat. The measurements were conducted with a sweep rate of 10 K/min. The Curie temperatures Tc were determined from DSC zero field measurements (heating curves.)

[0133] Magnetic measurements were performed using the Reciprocating Sample Option (RSO) mode in a Superconducting Quantum Interference Device (SQUID) magnetometer (Quantum Design MPMS 5XL). The magnetic entropy change S.sub.m is derived from the isofield magnetization measurements using the Maxwell relation.

Results

Crystal Structure

[0134] FIG. 1 shows the powder X-ray diffraction (XRD) patterns measured at 150 and 500 K (in the ferromagnetic and paramagnetic state, respectively) of materials of formula Mn.sub.1.25Fe.sub.0.70P.sub.0.5Si.sub.0.5N.sub.z with z=0.00, 0.01, 0.03, 0.05 and 0.07. All samples exhibit the hexagonal Fe.sub.2P-type crystal structure and, as often observed in this material family, display a small amount of (Mn,Fe).sub.3Si and MnO as impurity phases. With increasing nitrogen content the X-ray pattern gradually changes. No additional reflections are observed, indicating that the nitrogen is fully accommodated in the Fe.sub.2P-type of structure.

[0135] FIG. 2 shows the powder X-ray diffraction (XRD) patterns for materials of formula Mn.sub.1.25Fe.sub.0.70P.sub.0.5zSi.sub.0.5N.sub.z with z=0.00, 0.01, 0.03 and 0.07 (top) and for materials of formula Mn.sub.1.25Fe.sub.0.70P.sub.0.5Si.sub.0.5zN.sub.z with z=0.00, 0.01, 0.03 and 0.05 (bottom). In these materials either phosphorus atoms or silicon atoms of the corresponding parent material Mn.sub.1.25Fe.sub.0.70P.sub.0.5Si.sub.0.5 (z=0) are substituted by nitrogen atoms. The substitution of phosphorus atoms as well as of silicon atoms by nitrogen atoms does not result in a structural change relative to the corresponding parent material (z=0) when z=0.01. However, for z0.03 a Fe.sub.xN impurity phase is observed.

[0136] In FIGS. 1 and 2, the expression a.u. means arbitrary units.

Magnetocaloric Behavior

[0137] FIG. 3 shows the temperature dependence of the magnetization (magnetization curves) recorded on cooling and heating (sweeping rate 2 k/min) in a magnetic field of 1 T of materials of formula Mn.sub.1.25Fe.sub.0.70P.sub.0.5Si.sub.0.5N.sub.z with z=0.00, 0.01, 0.03, 0.05 and 0.07. The Curie temperature Tc decreases with increasing nitrogen content. On the other hand, increase of the nitrogen content leads to a gradual decrease in the spontaneous magnetization and a slight increase in thermal hysteresis. However, the hysteresis of all materials is relatively small thus revealing first-order nature of the magnetic transitions, which usually leads to a large magnetocaloric effect.

[0138] FIGS. 4A and 4B show the temperature dependence of the magnetization (magnetization curves) recorded on cooling and heating (sweeping rate 2 k/min) in a magnetic field of 1 T for materials of formula Mn.sub.1.25Fe.sub.0.70P.sub.0.5zSi.sub.0.5N.sub.z with z=0.00, 0.01, 0.03 and 0.07 (FIG. 4A) and for materials of formula Mn.sub.1.25Fe.sub.0.70P.sub.0.5Si.sub.0.5zN.sub.z with z=0.00, 0.01, 0.03 and 0.05 (FIG. 4B). The Curie temperature Tc as well as the spontaneous magnetization decreases faster with increasing nitrogen content, compared to the results shown in FIG. 3. Again, increase of the nitrogen content leads to a slight increase in thermal hysteresis.

[0139] The parameters Curie temperature Tc, thermal hysteresis Thys and magnetic entropy change Sm of the materials according to the invention and comparison materials (Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5 and Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53) are listed in table 2 hereinbelow:

TABLE-US-00002 TABLE 2 T.sub.c T.sub.Hys from DSC Sm Composition [K] [K] [Jkg1K1] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5 260 4.80 13.75 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.01 245 5.40 14.59 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.03 232 5.60 13.80 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.05 214 10.43 13.67 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.07 197 11.82 9.94 Mn.sub.1.25Fe.sub.0.7P.sub.0.49Si.sub.0.5N.sub.0.01 245 7.96 Mn.sub.1.25Fe.sub.0.7P.sub.0.47Si.sub.0.5N.sub.0.03 214 10.26 Mn.sub.1.25Fe.sub.0.7P.sub.0.43Si.sub.0.5N.sub.0.07 170 14.82 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.49N.sub.0.01 233 9.4 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.47N.sub.0.03 185 15.37 Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.45N.sub.0.05 151 22 Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53 288 4.3 17.7 Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53N.sub.0.01 280 3.4 14.8 MnFe.sub.0.95P.sub.0.45Si.sub.0.55N.sub.0.02 380 16 MnFe.sub.0.95P.sub.0.44Si.sub.0.5B.sub.0.06N.sub.0.02 400 1

[0140] From the last two samples in table 2 it is evident that presence of boron in certain cases results in a decrease of the thermal hysteresis.

Mechanical Stability

[0141] FIG. 5 demonstrates the effect of the presence of nitrogen atoms on the mechanical stability of magnetocaloric materials comprising manganese, iron, silicon and phosphorus when said materials are subject to thermal cycling. SEM (scanning electron microscopy) images of material samples were taken before thermal cycling (left part of FIG. 5) and after thermal cycling (right part of FIG. 5). In each case three thermal cycles between 50 C. and +50 C. were performed at a heating rate resp. cooling rate of 0.5 K/min.

[0142] The upper part of FIG. 5 shows SEM images (left sidebefore thermal cycling, right sideafter three thermal cycles as defined above) of a sample of a material according to the invention having the composition Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53N.sub.0.01. The lower part of FIG. 5 shows SEM images (left sidebefore thermal cycling, right sideafter three thermal cycles as defined above) of a sample of a comparison material having the composition Mn.sub.1.25Fe.sub.0.70P.sub.0.47Si.sub.0.53.

[0143] While the SEM image of the sample of the comparison material show that wide deep cracks have formed during thermal cycling, the SEM image of the sample of the material according to the invention does not show such cracks after thermal cycling. This is a further evidence that in magnetocaloric materials which comprise manganese, iron, silicon and phosphorus the presence of nitrogen atoms enhances the mechanical stability, compared to magnetocaloric materials comprising manganese, iron, silicon and phosphorus which do not comprise nitrogen atoms.

EMBODIMENTS

[0144] 1. A magnetocaloric material comprising [0145] manganese, and [0146] iron, and [0147] silicon, and [0148] phosphorus, and [0149] nitrogen, and [0150] optionally boron. [0151] 2. A magnetocaloric material according to embodiment 1 [0152] wherein the magnetocaloric material exhibits a hexagonal crystalline structure of the Fe.sub.2P type with a crystal lattice having the space group P-62m [0153] wherein nitrogen atoms occupy crystal sites and/or interstitial sites of said crystal lattice [0154] and wherein boron atoms if present occupy crystal sites of said crystal lattice according to the hexagonal crystal system with the space group P-62m, preferably 1b sites. [0155] 3. A magnetocaloric material according to embodiment 2, wherein [0156] nitrogen atoms occupy [0157] crystal sites of said crystal lattice having the space group P-62m, preferably crystal sites selected from the group consisting of 1b and 2c sites, [0158] and/or [0159] interstitial sites of said crystal lattice having the space group P-62m, preferably interstitial sites selected from the group consisting of 6k and 6j sites. [0160] 4. The magnetocaloric material according to any preceding embodiment, wherein the magnetocaloric material has a composition according to the general formula (I)

(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.vN.sub.zB.sub.w(I) [0161] wherein [0162] 0.1u0.1, preferably 0.05u0.05 [0163] 0.2x0.8, preferably 0.3x0.7, more preferably 0.35x0.65 [0164] 0.3y0.75, preferably 0.4y0.7 [0165] 0.25v0.7, preferably 0.3v0.6 [0166] 0w0.1, preferably 0.04w0.08 [0167] 0.001z0.1, preferably 0.005z0.07, more preferably 0.01z0.04 [0168] y+v+w1 [0169] y+v+z+w1. [0170] 5. The magnetocaloric material according to any of embodiments 1 to 4, wherein the magnetocaloric material has a composition according to the general formula (II)

(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.vN.sub.z(II) [0171] wherein [0172] 0.1u0.1, preferably 0.05u0.05 [0173] 0.2x0.8, preferably 0.3x0.7, more preferably 0.35x0.65 [0174] 0.3y0.75, preferably 0.4y0.7 [0175] 0.25v0.7, preferably 0.3v0.6 [0176] 0.001z0.1, preferably 0.005z0.07, more preferably 0.01z0.04 [0177] y+v1 [0178] y+v+z1 [0179] 0.001z0.1, preferably 0.005z0.07, more preferably 0.01z0.04. [0180] 6. The magnetocaloric material according to any of embodiments 1 to 4, wherein the magnetocaloric material has a composition according to the general formula (III)

(Mn.sub.xFe.sub.1).sub.2+uP.sub.ySi.sub.1yN.sub.z(III) [0181] wherein [0182] 0.1u0.1, preferably 0.05u0.05 [0183] 0.2x0.8, preferably 0.3x0.7, more preferably 0.35x0.65 [0184] 0.3y0.75, preferably 0.4y0.7 [0185] 0.001z0.1, preferably 0.005z0.07, more preferably 0.01z0.04. [0186] 7. The magnetocaloric material according to according to any of embodiments 1 to 4, wherein the magnetocaloric material has a composition according to the general formula (IV)

(Mn.sub.xFe.sub.1x).sub.2+uP.sub.ySi.sub.1yzN.sub.z(IV) [0187] wherein [0188] 0.1u0.1, preferably 0.05u0.05 [0189] 0.2x0.8, preferably 0.3x0.7, more preferably 0.35x0.65 [0190] 0.3y0.75, preferably, 0.4y0.7 [0191] 0.001z0.1, preferably 0.005z0.07, more preferably 0.01z0.04. [0192] 8. A magnetocaloric material according to any preceding embodiment, wherein the magnetocaloric material is selected from the group consisting of [0193] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.01 [0194] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.03 [0195] Mn.sub.1.25Fe.sub.0.7P.sub.0.49Si.sub.0.5N.sub.0.01 [0196] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.49N.sub.0.01 [0197] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.05 [0198] Mn.sub.1.25Fe.sub.0.7P.sub.0.5Si.sub.0.5N.sub.0.07 [0199] Mn.sub.1.25Fe.sub.0.7P.sub.0.47Si.sub.0.5N.sub.0.03 [0200] Mn.sub.1.25Fe.sub.0.7P.sub.0.43Si.sub.0.5N.sub.0.07 [0201] MnFe.sub.0.95P.sub.0.45Si.sub.0.55N.sub.0.02 [0202] MnFe.sub.0.95P.sub.0.44Si.sub.0.50B.sub.0.06N.sub.0.02. [0203] 9. Process for producing a magnetocaloric material according to any of embodiments 1 to 8, the process comprising the following steps: [0204] (a) providing a mixture of precursors comprising atoms of the elements manganese, iron, silicon, phosphorus, nitrogen, and optionally boron, wherein in said mixture of precursors the stoichiometric ratio of the total amounts of atoms of said elements corresponds to the stoichiometric ratio of the atoms of said elements in the magnetocaloric material produced in the process, and [0205] (b) reacting the mixture provided in step (a) in the solid and/or liquid phase obtaining a solid or liquid reaction product, and if the reaction product is a liquid reaction product, transferring the liquid reaction product into the solid phase obtaining a solid reaction product, and [0206] (c) optionally shaping of the solid reaction product obtained in step (b) to obtain a shaped solid reaction product, and [0207] (d) heat treatment of the solid reaction product obtained in step (b) or the shaped solid reaction product obtained in step (c) to obtain a heat treated product, and [0208] (e) cooling the heat treated product obtained in step (d) to obtain a cooled product, and [0209] (f) optionally shaping of the cooled product obtained in step (e). [0210] 10. Process according to embodiment 9, wherein said mixture of precursors comprises one more substances selected from the group consisting of elemental manganese, elemental iron, elemental silicon, elemental phosphorus, elemental boron, nitrides of iron, borides of iron, borides of manganese, phosphides of iron, phosphides of manganese, ammonia gas and nitrogen gas. [0211] 11. Process according to embodiment 9 or 10, wherein [0212] in step (b) reacting of the mixture comprises reacting of the mixture in the solid phase by ball-milling so that a reaction product in the form of a powder is obtained. [0213] 12. Process according to embodiment 9 or 11, wherein [0214] in step (b) reacting of the mixture comprises reacting of the mixture in the liquid phase and transferring the obtained liquid reaction product into the solid phase is carried out by quenching, melt-spinning or atomization. [0215] 13. Process according to embodiment 9 to 12, wherein in step (d) the heat treatment comprises sintering the solid reaction product obtained in step (b) or the shaped solid reaction product obtained in step (c). [0216] 14. The use of a magnetocaloric material according to any of embodiments 1 to 8 in a device selected from the group consisting of cooling systems, heat exchangers, heat pumps, thermomagnetic generators and thermomagnetic switches. [0217] 15. Device selected from the group consisting of cooling systems, heat exchangers, heat pumps, thermomagnetic generators and thermomagnetic switches, wherein said device comprises at least one magnetocaloric material according to any of embodiments 1 to 8.