A magnetocaloric cascade contains a sequence of magnetocaloric material layers having different Curie temperatures T.sub.C, wherein the magnetocaloric material layers include a cold-side outer layer, a hot-side outer layer and at least three inner layers between the cold-side outer layer and the hot-side outer layer, and each pair of next neighboring magnetocaloric layers of the magnetocaloric cascade has a respective Curie-temperature difference amount ΔT.sub.C between their respective Curie temperatures, wherein the hot-side outer layer or the cold-side outer layer or both the hot-side and cold-side outer layer exhibits a larger ratio mΔS.sub.max/ΔT.sub.C in comparison with any of the inner layers, m denoting the mass of the respective magnetocaloric material layer and ΔS.sub.max denoting a maximum amount of isothermal magnetic entropy change achievable in a magnetic phase transition of the respective magnetocaloric material layer.

A method of realizing a ferroic response is provided. The method includes applying a positive or negative conjugate field, which is of a first polarity, to a ferroic material to obtain a substantially minimized entropy of the ferroic material (301) and applying a slightly negative or a slightly positive conjugate field, which is of a second polarity opposite the first polarity, to the ferroic material to obtain a substantially maximized entropy of the ferroic material (302).

The invention relates to a magnetocaloric lattice element formed by fibres of magnetocaloric material, wherein the fibres are arranged in respective parallel lattice planes, each fibre having a respective mass of magnetocaloric material, the fibres of a given lattice plane do not contact each other but each fibre of a given lattice plane is attached to at least two fibres in a next neighbouring lattice plane, and wherein the magnetocaloric lattice element exhibits exactly one predominant mass-weighted direction of longitudinal fibre extension. When arranged in alignment of its predominant mass-weighted direction of longitudinal fibre extension with an external magnetic field, the magnetocaloric lattice element achieves an advantageous, particularly high magnetization of the magnetocaloric material, and as a consequence improves the performance of the magnetocaloric cooling device.

A process for liquefying a process gas that includes introducing a heat transfer fluid into an active magnetic regenerative refrigerator apparatus that comprises a single stage comprising dual multilayer regenerators located axially opposite to each other.

A polymeric material having a negative photoelastic constant. The polymeric material comprises: (a) a polymer comprising polymerized units of 2-vinylpyridine, 4-vinylpyridine, methyl methacrylate or a combination thereof; (b) a C.sub.9-C.sub.25 aliphatic polycyclic compound; and (c) an organic compound having a boiling point of at least 200° C.

A process for liquefying a process gas that includes introducing a heat transfer fluid into an active magnetic regenerative refrigerator apparatus that comprises a single stage comprising dual multilayer regenerators located axially opposite to each other.

In various aspects, methods of making perovskite manganese oxide particles are provided as well as perovskite manganese oxide particles made therefrom. The perovskite manganese oxide particles exhibit a strong magnetocaloric effect, making them well suited for applications in power generation and magnetic refrigeration, especially at or near room temperature. The methods can include forming an aqueous mixture of (i) a low-molecular-weight polymeric polyalcohol gel precursor, (ii) a stoichiometric amount of metal salts or hydrates thereof, wherein the metal salts or hydrates thereof comprise at least a Manganese (Mn), and (iii) a polybasic carboxylic acid; polymerizing the aqueous mixture to form a gel containing perovskite manganese oxide nanoparticles entrapped therein; and calcining the gel to remove at least a portion of organic material in the gel and form the perovskite manganese oxide particles. Method and systems are also provided for power generation and magnetic refrigeration using the perovskite manganese oxide particles.

A magnetic structure has a magnetocaloric material the temperature of which changes with application or removal of a magnetic field, and a high thermal conduction member which is in contact with the magnetocaloric material and has higher thermal conductivity than the magnetocaloric material. Further, this magnetic air-conditioning and heating device is provided with multiple of the aforementioned magnetic structures, a thermal switch which is arranged between magnetic structures and transmits or insulates heat, and a magnetic field varying unit which applies or removes a magnetic field to each of the magnetic structures. By providing in the magnetic structures a high thermal conduction member with higher thermal conductivity than the magnetocaloric material, some or all of the heat generated in the magnetocaloric material can be quickly conducted in the magnetic bodies.

A process for liquefying a process gas that includes introducing a heat transfer fluid into an active magnetic regenerative refrigerator apparatus that comprises a single stage comprising dual multilayer regenerators located axially opposite to each other.

A magnetocaloric lattice element formed by fibres of magnetocaloric material, wherein the fibres are arranged in respective parallel lattice planes, each fibre having a respective mass of magnetocaloric material, the fibres of given lattice plane do not contact each other but each fibre of a given lattice plane is attached to at least two fibres in a next neighbouring lattice place, and wherein the magnetocaloric lattice element exhibits exactly one predominant mass-weighted direction of longitudinal fibre extension.