Magnetization orientation dependence of the quasiparticle spectrum and hysteresis in ferromagnetic metal nanoparticles

Physical Review B - Condensed Matter and Materials Physics

Volumn 66, Issue 9, 2002, Pages 1-15

  Cehovin, A ^a   Canali, C M ^a,b   MacDonald, A H ^c  

^a LUND UNIVERSITY   (Sweden)

^b LINNAEUS UNIVERSITY   (Sweden)

^c UNIVERSITY OF TEXAS AT AUSTIN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 85038928778     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.66.094430     Document Type: Article

References (45)

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42. This scenario neglects the possibility of quantum tunneling between the two local minima through the energy barrier separating them. At low fields and for nanoparticles of 1-4 nanometers in diameter, quantum tunneling is exponentially small.
43. Clearly, if the external field is not in the (formula presented) plane, the magnetization will not stay exactly in this easy plane. However, the displacement of the magnetization from easy to hard directions is negligible at the weak fields (formula presented) (see Fig. 1515) and it becomes relevant only at larger fields, when the component of the magnetization in the (formula presented) plane is essentially frozen along the direction of the component of (formula presented) in that plane.
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45. The quasiparticle energy difference on the opposite sides of the transition is of the order of the typical quasiparticle anisotropy energy. For the nanoparticles that we can study numerically this energy is smaller than the mean-level spacing. However, for larger particles the energy difference at the transition can be larger than (formula presented) In this case the jumps at the switching fields will cause a complete reshuffling of the quasiparticle levels.