Demonstration of Spin Current Switch across Ferro‐Antiferromagnetic Transition

Abstract

The first-order magnetic phase transition between antiferromagnetic (AFM) and ferromagnetic (FM) states around room temperature is one of the unique features in FeRh. More fascinating is that the phase-transition temperature (T tr) can be readily modulated by the magnetic field. In this work, a spin current valve is isothermally demonstrated by electrically and thermally probing the spin channel during the phase transition. When switching between the AFM and FM states, a large magnetoresistance ratio of 50% is obtained. Meanwhile, the on/off ratio for the magnetospin-polarized thermal voltage associated with the magnonic spin current can be nearly infinite. It is shown that the significantly modulated T tr and switching critical field in FeRh advance its potential applications for the spin current switch devices.

The Magnetic Phase Transition of FeRh Modulated by AC Magnetic Field

“…[1,2] The large magnetic entropy and lattice entropy are also caused during phase transition, [2,3] which makes it attractive in the fields of refrigerations, [2][3][4][5] sensings, and energy conversions. [5][6][7] FeRh with a CsCl-type structure is a typical FOMPT material with the transition temperature from antiferromagnetic (AFM) to ferromagnetic (FM) state at about 370 K. [8][9][10][11] Meanwhile, the phase transition leads to an isotropic volume expansion of about 1%, [10] a decrease in resistivity of about 50%, [12,13] and a large thermal hysteresis. [14,15] The previous research shows that FeRh is easily manipulated by temperature, [11] doping, [14] stress, [16,17] magnetic field, [18][19][20][21][22] electric field, [6,7,23,24] spin current, [10,25] ionic liquid, [26] etc.…”