Experimental observation of ferroelectricity in ferrimagnet MnCr2S4

Abstract

Ferrimagnetic spinel compounds AB2X4 (A and B are the magnetic transition elements) are considered to be promising candidates for multiferroics with large magnetization and polarization. In this work, we synthesize polycrystalline spinel MnCr2S4 and characterize the magnetic and ferroelectric properties. Two well-defined ferroelectric phase transitions are demonstrated. The first one occurs at the Cr3+ ferromagnetic phase transition temperature of TC = 65 K, and the other takes place at the Yafet–Kittel (YK) magnetic phase transition temperature of TYK ≈ 5 K. It is suggested that ferroelectricity in the YK phase is driven by the noncollinear triangular YK spin orders and can be greatly tuned by an external magnetic field. Between TYK and TC ranges, another opposite electric polarization sublattice appears, which is enhanced by the external magnetic field just near TC, revealing that this opposite electric polarization is likely related to magnetostriction and the magnetic field can enhance the lattice distortions near TC. Thus, this work paves the way for exploiting ferrimagnetic multiferroicity although more studies are needed to clarify the ferroelectricity mechanism in the Cr3+ ferromagnetic phase.

Nanoscale Magnetization Reversal by Magnetoelectric Coupling Effect in Ga0.6Fe1.4O3 Multiferroic Thin Films

“…Multiferroic materials, which possess two or more ferroic orders simultaneously, such as spontaneous electric polarization and magnetization in a single phase, have attracted more attention because of their intriguing physics and novel technological applications. − In particular, if these systems have magnetoelectric (ME) coupling effect, they could provide an useful avenue for the development of novel devices based on new functionalities such as control of the magnetic properties by means of electrical fields and vice versa. , Over the past decades, numerous single-phase multiferroics have been presented by advanced preparation techniques and first-principle calculations, such as ferroelectric-antiferromagnetic (Bi, Gd, Dy, Yb, Sm, La, and Lu) FeO 3 , − (Dy, Gd, and Tb) CrO 3 , , (Sr, Y, Dy, Tb, and Ho) MnO 3 , − and (Mn, Fe, Co) 2 Mo 3 O 8 , , ferroelectric–ferrimagnetic Fe 3 O 4 and MnCr 2 S 4 , , ferroelectric–ferromagnetic EuTiO 3 , and so on. − Unfortunately, the available materials are still lacking and elusive because of their antiferromagnetic nature or low working temperature ( T w ). Thus, it is vital to continue exploring new multiferroic materials possessing high T w , strong ferromagnetism, and a strong ME coupling effect for the practical application. , …”