The present invention relates to a room-temperature multiferroicity material, a method for preparing same, and an electronic device comprising same. According to an example embodiment of the present invention, a room-temperature multiferroicity material according to an aspect of the present disclosure comprises a compound in chemical Formula (2) below in a compound matrix in chemical formula (1) below. Chemical formula (1) (Pb.sub.1-xTM.sub.x)Fe.sub.1/2Nb.sub.1/2O.sub.3 (in chemical formula (1), TM comprises at least one selected from the group consisting of Fe, Ni and Co, and x is a number greater than 0 and smaller than 1). Chemical formula (2) ABO.sub.3 (in chemical formula (2), A comprises at least one selected from the group consisting of Pb, Bi and Ba, and B comprises Ti and/or Zr).

The present invention relates to a ferrite particle, containing a crystal phase component containing a perovskite crystal represented by the compositional formula:

RZrO.sub.3 (provided that R represents an alkaline earth metal element), and having an apparent density in a range represented by the following formula:

1.90≤Y≤2.45

provided that Y in the formula is the apparent density (g/cm.sup.3) of the ferrite particle.

A method for producing a solid composition according to the present disclosure is a method for producing a solid composition that is used for forming a functional ceramic having a first crystal phase. The method for producing a solid composition includes: producing an oxide composed of a second crystal phase different from the first crystal phase; and mixing the oxide and an oxo acid compound.

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 of forming a single phase compositionally complex material including a plurality of transition metals is provided. The method includes creating a magnetic phase diagram to predict magnetic behavior, by calculating expected magnetic states and calculating the spin structure factor by Fourier transform; calculating the spin structure factor by Fourier transform; obtaining a transition temperature from the spin structure factor; selecting the plurality of transition metals and corresponding transition metal composition ratios for the material based on a desired magnetic behavior and the calculated spin structure factor; and forming the material that is a compositionally complex transition metal oxide comprising the plurality of transition metals at the selected composition ratios. The material may be a compositionally complex ABO.sub.3 perovskite film in which A is La and B is the plurality of transition metals including Cr, Mn, Fe, Co, and Ni.

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.

The present invention provides: a ferrite particle containing a crystal phase component containing a perovskite crystal represented by the compositional formula RZrO.sub.3 (where R is an alkaline earth metal element); and an electrophotographic developer carrier core material, an electrophotographic developer carrier, and an electrophotographic developer containing the ferrite particles.

A method for producing a solid composition according to the present disclosure is a method for producing a solid composition that is used for forming a functional ceramic having a first crystal phase. The method for producing a solid composition includes: producing an oxide composed of a second crystal phase different from the first crystal phase; and mixing the oxide and an oxo acid compound.

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 (0.5x0.5, 0.5y0.5). 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.

The present invention relates to new multiferroic materials. More particularly, the present invention relates to new multiferroic single phase ceramic materials as well as to thin films formed from these materials, methods of preparing these materials and their use as multiferroic materials in electronic components and devices.