Disclosed is a ferromagnetic element-substituted room-temperature multiferroic material having ferromagnetism and ferroelectricity at room temperature, wherein the ferromagnetic element-substituted room-temperature multiferroic material includes a compound of chemical formula 1: <chemical formula 1> (Pb.sub.1-xM.sub.x)Fe.sub.1/2Nb.sub.1/2O.sub.3. In chemical formula 1, M represents a ferromagnetic element, and x represents a number greater than 0 and smaller than 1.

A method for manufacturing diamond substrate of using source gas containing hydrocarbon gas and hydrogen gas to form diamond crystal on an underlying substrate by CVD method, to form a diamond crystal layer having nitrogen-vacancy centers in at least part of the diamond crystal, nitrogen or nitride gas is mixed in the source gas, wherein the source gas is: 0.005 volume % or more and 6.000 volume % or less of the hydrocarbon gas; 93.500 volume % or more and less than 99.995 volume % of the hydrogen gas; and 5.0×10.sup.−5 volume % or more and 5.0×10.sup.−1 volume % or less of the nitrogen gas or the nitride gas, and the diamond crystal layer having the nitrogen-vacancy centers is formed. A method for manufacturing a diamond substrate to form an underlying substrate, a diamond crystal having a dense nitrogen-vacancy centers (NVCs) with an orientation of NV axis by performing the CVD.

A method for manufacturing diamond substrate of using source gas containing hydrocarbon gas and hydrogen gas to form diamond crystal on an underlying substrate by CVD method, to form a diamond crystal layer having nitrogen-vacancy centers in at least part of the diamond crystal, nitrogen or nitride gas is mixed in the source gas, wherein the source gas is: 0.005 volume % or more and 6.000 volume % or less of the hydrocarbon gas; 93.500 volume % or more and less than 99.995 volume % of the hydrogen gas; and 5.0×10.sup.−5 volume % or more and 5.0×10.sup.−1 volume % or less of the nitrogen gas or the nitride gas, and the diamond crystal layer having the nitrogen-vacancy centers is formed. A method for manufacturing a diamond substrate to form an underlying substrate, a diamond crystal having a dense nitrogen-vacancy centers (NVCs) with an orientation of NV axis by performing the CVD.

A magnetic material is constituted of a ferromagnetic or ferrimagnetic insulator in a double perovskite structure of Sr.sub.3-xA.sub.xOs.sub.1-yB.sub.yO.sub.6 (0.5≤x≤0.5, −0.5≤y≤0.5). A is an alkali metal or alkaline earth metal atom, and B is a transition metal atom, alkali metal atom, or alkaline earth metal atom). The insulator may be Sr.sub.3OsO.sub.6, where x=y=0 in the above formula. Sr.sub.3OsO.sub.6 is formed to have a cubic crystal structure where strontium atoms, osmium atoms, and oxygen atoms are arranged at lattice points.

A structure includes an electronically controllable ferromagnetic oxide structure that includes at least three layers. The first layer comprises STO. The second layer has a thickness of at least about 3 unit cells, said thickness being in a direction substantially perpendicular to the interface between the first and second layers. The third layer is in contact with either the first layer or the second layer or both, and is capable of altering the charge carrier density at the interface between the first layer and the second layer. The interface between the first and second layers is capable of exhibiting electronically controlled ferromagnetism.

A structure includes an electronically controllable ferromagnetic oxide structure that includes at least three layers. The first layer comprises STO. The second layer has a thickness of at least about 3 unit cells, said thickness being in a direction substantially perpendicular to the interface between the first and second layers. The third layer is in contact with either the first layer or the second layer or both, and is capable of altering the charge carrier density at the interface between the first layer and the second layer. The interface between the first and second layers is capable of exhibiting electronically controlled ferromagnetism.

The invention relates to hard magnets that include an intermetallic compound having the general composition

X.sub.aX′.sub.bY.sub.cZ.sub.d where X and X′ independently from one another are representative of a 3d transition metal with unpaired electrons; Y is a 4d or 5d transition metal of groups 5, 8, 9, or 10 Z is a main group element of groups 13, 14 or 15; a and d independently from one another represent a number between 0.1 and 2.0; and b and c independently from one another represent a number between 0.0 and 2.0; such that a+b+c+d is between 3.0 and 4.0.

A method for manufacturing diamond substrate of using source gas containing hydrocarbon gas and hydrogen gas to form diamond crystal on an underlying substrate by CVD method, to form a diamond crystal layer having nitrogen-vacancy centers in at least part of the diamond crystal, nitrogen or nitride gas is mixed in the source gas, wherein the source gas is: 0.005 volume % or more and 6.000 volume % or less of the hydrocarbon gas; 93.500 volume % or more and less than 99.995 volume % of the hydrogen gas; and 5.0×10.sup.−5 volume % or more and 5.0×10.sup.−1 volume % or less of the nitrogen gas or the nitride gas, and the diamond crystal layer having the nitrogen-vacancy centers is formed. A method for manufacturing a diamond substrate to form an underlying substrate, a diamond crystal having a dense nitrogen-vacancy centers (NVCs) with an orientation of NV axis by performing the CVD.

A device including a multi-layered structure that includes: a first layer that includes a first magnetic Heusler compound; a second layer that is non-magnetic at room temperature and includes both Ru and at least one other element E, wherein the composition of the second layer is represented by Ru1−xEx, with x being in the range from 0.45 to 0.55; and a third layer including a second magnetic Heusler compound. The multi-layered structure may overlay a substrate. The device may include a tunnel barrier overlying the multi-layered structure.

Devices are described that include a multi-layered structure that comprises three layers. The first layer is a magnetic Heusler compound, the second layer (acting as a spacer layer) is non-magnetic at room temperature and comprises alternating layers of Ru and at least one other element E (preferably Al; or Ga or Al alloyed with Ga, Ge, Sn or combinations thereof), and the third layer is also a magnetic Heusler compound. The composition of the second layer is represented by Ru.sub.1xE.sub.x, with x being in the range from 0.45 to 0.55. An MRAM element may be constructed by forming, in turn, a substrate, the multi-layered structure, a tunnel barrier, and an additional magnetic layer (whose magnetic moment is switchable).