Voltage control of magnetic hysteresis in a nickel nanoparticle

作者：Gartland P^*; Jiang W; Davidovic D

来源：Physical Review B, 2015, 91(23): 235408.

DOI：10.1103/PhysRevB.91.235408

The effects of voltage bias on magnetic hysteresis in single Ni particles 2 to 3 nm in diameter are measured between temperatures of 60 mK and 4.2 K by using sequential electron tunneling through the particle. While some Ni particles do not display magnetic hysteresis in tunneling current versus magnetic field, in the Ni particles that display hysteresis, the effect of bias voltage on magnetic switching field is nonlinear. The magnetic switching field changes weakly in the voltage interval similar to 1 mV above the tunneling onset voltage, and rapidly decreases versus voltage above that interval. A voltage-driven mechanism explaining this nonlinear suppression of magnetic hysteresis is presented, where the key effect is a magnetization blockade due to the addition of spin-orbit anisotropy epsilon(so) to the particle by a single electron. A necessary condition for the particle to exhibit magnetization blockade is that epsilon(so) increases when the magnetization is slightly displaced from the easy axis. In that case, an electron will be energetically unable to access the particle if the magnetization is sufficiently displaced from the easy axis, which leads to a voltage interval where magnetic hysteresis is possible that is comparable to epsilon(so)/e, where e is the electronic charge. If epsilon(so) decreases vs magnetization displacement from the easy axis, there is no magnetization blockade and no hysteresis.

• 出版日期2015-6-8