Rothman J, Kläui M, Lopez-Diaz L, Vaz C A, Bleloch A, Bland J A, Cui Z, Speaks R
Cavendish Laboratory, University of Cambridge, United Kingdom.
Phys Rev Lett. 2001 Feb 5;86(6):1098-101. doi: 10.1103/PhysRevLett.86.1098.
We present the results of a study of the magnetic properties of an array of 34-nm thick Co(100) epitaxial ring magnets, with inner and outer diameters of d(in) = 1.3 microm and d(out) = 1.6 microm, respectively. Magnetic measurements and micromagnetic simulations show that a two step switching process occurs at high fields, indicating the existence of two different stable states. In addition to the vortex state, which occurs at intermediate fields, we have identified a new bi-domain state, which we term the onion state, corresponding to opposite circulation of the magnetization in each half of the ring. The onion state is stable at remanence and undergoes a simple and well characterized nucleation free switching.
我们展示了一项关于一系列34纳米厚的Co(100)外延环形磁体的磁性研究结果，其内径d(in) = 1.3微米，外径d(out) = 1.6微米。磁性测量和微磁模拟表明，在高场下会发生两步切换过程，这表明存在两种不同的稳定状态。除了在中间场出现的涡旋态，我们还识别出一种新的双畴态，我们将其称为洋葱态，它对应于环的每一半中磁化强度的相反环流。洋葱态在剩磁时是稳定的，并且经历简单且特征明确的无成核切换。
