scholarly journals The Magnetic Properties of Closely Spaced Three-Dimensional Nanomagnet Array

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Ying Li ◽  
Tianxing Wang ◽  
Heyan Liu ◽  
Xuefang Dai ◽  
Xiao Yu ◽  
...  

With Monte Carlo method, we investigate the magnetic ground state, magnetic specific heat, and magnetic hysteresis loop for three types of closely spaced nanomagnet arrays in three-dimensional (3D) space. It is found that the magnetic ground state of three nanomagnet arrays exhibits the vortex order, caused by the long-range dipolar interactions. Three types of nanomagnet arrays have almost the same magnetic transition temperature even if their array formation in 3D triangular lattice is different. Some slight jump occurs in the hysteresis loop of the face-centered cubic nanomagnet array, while for the simple hexagonal nanomagnet and close-packed hexagonal nanomagnet arrays no jump is found.

1990 ◽  
Vol 202 ◽  
Author(s):  
Bruce A. Andrien ◽  
David R. Miller

ABSTRACTThin Fe films, 1 nm to 90 nm, have been grown on GaAs (100) substrates in ultra high vacuum, base pressure = 2×l0−8 Pa. The growth of the films has been followed with Auger electron spectroscopy and a recently developed in-situ UHV M/H hysteresis loop tracer. The Auger signal provides an indication as to when the Fe covers the GaAs substrate or when it clusters into three dimensional islands. The magnetic hysteresis loop tracer provides the coercivity and the saturation magnetic moment, from which the saturation magnetization or average film thickness can be obtained. The coercivity of thin films is sensitive to structure, strain, and to the grain size, in analogy to its sensitivity to particle size for small particles. The data show that the coercivity, Hc, as a function of film thickness, is very sensitive to the annealing procedures and to the resulting morphology, continuous versus local clustering of the iron film. Under proper conditions a clear maximum in Hc versus film thickness is observed for these films near 5 nm thickness, in analogy to three dimensional small particle curves.


1996 ◽  
Vol 35 (Part 1, No. 7) ◽  
pp. 3882-3886 ◽  
Author(s):  
Masaru Nakamura ◽  
Tsukasa Hirayama ◽  
Yasuji Yamada ◽  
Yuichi Ikuhara ◽  
Yuh Shiohara

2008 ◽  
Vol 47 (12) ◽  
pp. 9013-9015 ◽  
Author(s):  
Guillemin Rodary ◽  
Sebastian Wedekind ◽  
Dirk Sander ◽  
Jürgen Kirschner

2012 ◽  
Vol 190 ◽  
pp. 291-294
Author(s):  
Igor A. Abrikosov ◽  
Marcus Ekholm ◽  
Alena V. Ponomareva ◽  
Svetlana A. Barannikova

We demonstrate the importance of accounting for the complex magnetic ground state and finite temperature magnetic excitations in theoretical simulations of structural and elastic properties of transition metal alloys. Considering Fe72Cr16Ni12face centered cubic (fcc) alloy, we compare results of first-principles calculations carried out for ferromagnetic and non-magnetic states, as well as for the state with disordered local moments. We show that the latter gives much more accurate description of the elastic properties for paramagnetic alloys. We carry out a determination of the magnetic ground state for fcc Fe-Mn alloys, considering collinear, as well as non-collinear states, and show the sensitively of structural and elastic properties in this system to the detailed alignment between magnetic moments. We therefore conclude that it is essential to develop accurate models of the magnetic state for the predictive description of properties of transition metal alloys.


2007 ◽  
Vol 40 (2) ◽  
pp. 173-178 ◽  
Author(s):  
J.N. Mohapatra ◽  
A.K. Panda ◽  
M.K. Gunjan ◽  
N.R. Bandyopadhyay ◽  
A. Mitra ◽  
...  

2014 ◽  
Vol 898 ◽  
pp. 173-176
Author(s):  
Jun Zhang ◽  
Hai Rui Yao ◽  
Hua Bo Li ◽  
Jing Jing Li ◽  
Xiao Kang Bai

Hexagonal Ni micro/nanoplates were successfully prepared via a facile hydrothermal route using the polyvinylpyrrolidone as structure-directing agent. It has been verified from x-ray powder diffraction and transmission electronic microscopy that as-prepared products with high purity and fine dispersity belong to face-centered cubic microstructure of nickel metal. The magnetic hysteresis loop of the hexagonal Ni micro/nanoplates exhibits the ferromagnetic characteristics, and its coercivity increases by 25 % in comparison with the bulk nickel materials. The possible mechanism of the formation of hexagonal micro/nanoplates was suggested.


2014 ◽  
Vol 875-877 ◽  
pp. 272-276 ◽  
Author(s):  
Chao Jing ◽  
Ye Jun Yang ◽  
Dong Hua Yu ◽  
Zhe Li ◽  
Xiao Long Wang ◽  
...  

We report the exchange bias properties in the bulk Ni45Co5Mn38Sn12quaternary Heusler alloy. The ferromagnetic (FM) –antiferromagnetic (AFM) interactions get reinforced after the Co substitution for Ni in the Ni-Mn-Sn alloy, which increase the exchange bias field (HE). A maximum shift in hysteresis loops of 306 Oe was observed in the 10 kOe field cooled sample. The origin of this large exchange bias field has been discussed. Magnetic hysteresis loop obtained in the zero field cooled (ZFC) mode shows double-shifted loop, and the reason of this phenomenon has been explained in detail.


2021 ◽  
Vol 19 (10) ◽  
pp. 20-28
Author(s):  
Dhifaf Hussain Hassan ◽  
Sabah Jalal Fathi

The compound was prepared by sol-gel method for spontaneous combustion with certain weight ratios (x=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9), the samples were calcined at a temperature (900oC) for a period of two hours(2h), then studied its structural and magnetic properties.one of the most prominent results that we obtained from the X-ray diffraction technique (XRD) is that compound has several phases. Where the sample (NiFe2O4) appeared to be polycrystalline and the dominant phase in it is the cubic phase, while the other phase is (Hematite)(Fe2O3) A crystal structure rhomboid (Rhombohedral), in addition to these two phases, the phase with the existing quaternary structure appeared (Sr2Fe2O5) its called (Orthorhombic). The results of the magnetic properties that were obtained through the (VSM) device, and one of the most important of these properties is the magnetic hysteresis loop by analyzing the magnetic hysteresis loop at (x=0.3), where the least area of the hysteresis loop or the least width of the hysteresis loop One of the most important parameters of the magnetic properties is the saturation magnetism (μS) and its value ranges from (19.76-3.86) (emu/gr), the highest value was at (X=0.3) and its value is (19.76emu/gr) and in general its value decreases with increasing concentration of strontium. The residual magnetism (Mr) ranges between (7.45-1.58) (emu/gr), where it reached its highest value at (x=0.3) and its value is (7.45emu/gr), and generally its value decreases with increasing concentration of strontium. In addition to that, there is another parameter which is coercion or Magnetic coercivity (Hc) ranges in value (1751.104-209.26) (Oe), reaching its lowest value at (x=0.3), and then increases with increasing strontium concentration until it reaches its highest value at (x=0.9), where it reached its value is (1751.104Oe). The square rate represented by the symbol (μi) has high values. This means that there is a mutual coupling between the soft and hard magnetic phases, which was the highest value at (x=0.3) and its value is (4.93).


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