scholarly journals Magnetic interaction and anisotropy axes arrangement in nanoparticle aggregates can enhance or reduce the effective magnetic anisotropy

2020 ◽  
Vol 498 ◽  
pp. 166170
Author(s):  
V.R.R. Aquino ◽  
L.C. Figueiredo ◽  
J.A.H. Coaquira ◽  
M.H. Sousa ◽  
A.F. Bakuzis
2006 ◽  
Vol 45 ◽  
pp. 2528-2533 ◽  
Author(s):  
S. Srinath ◽  
N.A. Frey ◽  
H. Srikanth ◽  
G.X. Miao ◽  
A. Gupta

We have investigated the exchange bias in CVD grown epitaxial CrO2/Cr2O3 bilayer thin films using hysteresis loops and resonant RF transverse susceptibility. M-H loops indicated an enhanced coercivity without appreciable loop shift and the transverse susceptibility in CrO2/Cr2O3 bilayers revealed features associated with both the ferromagnetic and antiferromagnetic phases. In addition, TS yielded large anisotropy constant (Keff) values depending on the fraction of Cr2O3 present. The large anisotropy fields observed cannot be accounted for by the variable thickness of CrO2 alone and are indicative of possible exchange coupling between CrO2 and Cr2O3 phases that significantly affects the effective magnetic anisotropy.


2019 ◽  
Vol 5 (1) ◽  
pp. 33-39
Author(s):  
Alexey S. Semenov ◽  
Aleksey G. Nalogin ◽  
Sergey V. Shcherbakov ◽  
Alexander V. Myasnikov ◽  
Igor M. Isaev ◽  
...  

In this work we have considered metrological problems and measurement of magnetic parameters and presented methods of measuring effective magnetic anisotropy field HAeff and ferromagnetic resonance bandwidth ∆H in magnetically uniaxial hexagonal ferrites in the electromagnetic microwave working frequency range. The methods allow measuring HAeff in the 10–23 and 28–40 kE ranges and ∆H in the 0.5–5.0 range. One method (suitable for wavelength measurements in free space in the 3-mm wavelength range) has been implemented for the 78.33–118.1 GHz range. The other method (based on the use of microstrip transmission lines) has been implemented for the 25–67 GHz range. The methods have been tested for polycrystalline specimens of hexagonal barium and strontium ferrites with nominal composition or complex substituted and having high magnetic texture. The measurement results have been compared with those obtained using conventional measurement methods and spherical specimens. Our methods prove to be highly accurate and reliable.


2006 ◽  
Vol 512 ◽  
pp. 165-170
Author(s):  
Yu Shiratsuchi ◽  
Yasushi Endo ◽  
Masahiko Yamamoto

We have investigated the magnetism of ultrathin Fe films grown on the inclined Al2O3(0001), especially, in the vicinity of ferromagnetic-superparamagnetic transition. In the transition region, the magnetic state of Fe films is the coexistence of ferromagnetism and superparamagnetism. The ratio of the components in ferromagnetic and superparamagnetic state is dependent on the growth temperature. For Fe grown on the flat substrate without the inclination, as the growth temperature increases, the ratio of the component in ferromagnetic state increases, reaches to the maximum and decreases again. On the presence of substrate inclination, the ratio of the component in ferromagnetic state increases, reaches to the maximum and decreases again. decreases monotonically with increasing growth temperature. We investigated the dominant factor of the complex magnetic state, and clarified that the complex magnetic state is dominated by the change of the film structure and the effective magnetic anisotropy energy.


2001 ◽  
Vol 89 (11) ◽  
pp. 6422-6425 ◽  
Author(s):  
G. R. Aranda ◽  
C. Miguel ◽  
P. Garcı́a-Tello ◽  
J. González

1993 ◽  
Vol 74 (11) ◽  
pp. 6788-6790 ◽  
Author(s):  
Kai‐Yuan Ho ◽  
Xiang‐Yuan Xiong ◽  
Jing Zhi ◽  
Li‐Zhi Cheng

2007 ◽  
Vol 56 (3) ◽  
pp. 1697
Author(s):  
Han Xian-Tang ◽  
Wang Zhi ◽  
Ma Xiao-Hua ◽  
Wang Guang-Jian

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