Quantum spin tunneling of magnetization in small ferromagnetic particles

Abstract

a b s t r a c tAn approach is presented that can also account for the description of small ferromagnetic particle magnetization tunneling. An estimate of the saturation value of an external applied magnetic field along the easy axis is obtained. An analytic expression for the tunneling factor in the absence of an external magnetic field is deduced from the present approach that also allows one to obtain the crossover temperature characterizing the regime where tunneling is dominated by quantum effects.

Spin transition nanoparticles made electrochemically

“…However, the Néel temperature has not been suppressed as described in the synthesis of a single crystal of herbertsmithite. 3 This result may be explained by the fact that below a critical size, magnetic particles become single domain in contrast with the usual multidomain structure of microcrystalline samples, which can exhibit unique phenomena such as unusual coercivities, 34 quantum tunneling of the magnetization, 35,36 and superparamagnetism. 37,38 Another possible explanation for this is that the size reduction of herbertsmithite could affect the novel magnetic properties, due to the small volume or the high surface/volume ratio (spin canting effect), 39,40 a phenomenon through which spins show a lack of full alignment at the surface.…”

Observation of spin-1 tunneling on a quantum computer

“…Quantum spin tunneling is phenomena where single spin tunnels between two opposite directions. This leads to degeneracy of energy levels related with opposite states which is called quantum spin tunneling splitting (see, for instance, [15,16]). Experimental observation of quantum tunneling of the magnetization of cluster with S = 10 was reported in [17].…”