Voltage controlled Néel vector rotation in zero magnetic field

Abstract

Multi-functional thin films of boron (B) doped Cr ₂O ₃ exhibit voltage-controlled and nonvolatile Néel vector reorientation in the absence of an applied magnetic field, H. Toggling of antiferromagnetic states is demonstrated in prototype device structures at CMOS compatible temperatures between 300 and 400 K. The boundary magnetization associated with the Néel vector orientation serves as state variable which is read via magnetoresistive detection in a Pt Hall bar adjacent to the B:Cr ₂O ₃ film. Switching of the Hall voltage between zero and non-zero values implies Néel vector rotation by 90 degrees. Combined magnetometry, spin resolved inverse photoemission, electric transport and scanning probe microscopy measurements reveal B-dependent T _N and resistivity enhancement, spin-canting, anisotropy reduction, dynamic polarization hysteresis and gate voltage dependent orientation of boundary magnetization. The combined effect enables H = 0, voltage controlled, nonvolatile Néel vector rotation at high-temperature. Theoretical modeling estimates switching speeds of about 100 ps making B:Cr ₂O ₃ a promising multifunctional single-phase material for energy efficient nonvolatile CMOS compatible memory applications.

Abstract

Voltage control of magnetization is critical for the development of antiferromagnetic spintronics. Here, using magnetic force microscopy and Hall measurements, Mahmood et al. demonstrate controlled rotation of the Néel vector in a heterostructure composed of Pt and antiferromagnetic B:Cr ₂O ₃.