scholarly journals The Influence of Pressure on the Formation of FM/AF Configurations in LSMO Films: A Monte Carlo Approach

Computation ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 93
Author(s):  
Hugo Hernán Ortiz-Álvarez ◽  
Francy Nelly Jiménez-García ◽  
Carolina Márquez-Narváez ◽  
José Dario Agudelo-Giraldo ◽  
Elisabeth Restrepo-Parra

In this work, Monte Carlo simulations of magnetic properties of thin films, including the influence of an external pressure, are presented. These simulations were developed using a Hamiltonian composed by terms that represent the exchange interaction, dipolar interaction, Zeeman effect, monocrystalline anisotropy, and pressure influence. The term that represents the pressure influence on the magnetic properties was included, since for many applications, magnetic materials are a part of a multiferroic material together with a piezoelectric or a ferroelectric compound. Initially, the model was developed using generic parameters, in order to probe its suitable performance; after that, parameters were adjusted for simulating thin films of La0.67Sr0.33MnO3, a manganite with several technological applications because its Curie temperature is greater than room temperature. Including the pressure influence, it was observed the formation of several kind of FM/AF configurations as strip, labyrinth, and chess board forms. Furthermore, it was observed that, as the pressure increased, the critical temperature tended to decrease, and this result was in agreement with experimental reports.

2012 ◽  
Vol 501 ◽  
pp. 236-241 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah ◽  
Ramadan E. Shaiboub

Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.


2013 ◽  
Vol 690-693 ◽  
pp. 1702-1706 ◽  
Author(s):  
Shuang Jun Nie ◽  
Hao Geng ◽  
Jun Bao Wang ◽  
Lai Sen Wang ◽  
Zhen Wei Wang ◽  
...  

NiZn-ferrite thin films were deposited onto silicon and glass substrates by radio frequency magnetron sputtering at room temperature. The effects of the relative oxygen flow ratio on the structure and magnetic properties of the thin films were investigated. The study results reveal that the films deposited under higher relative oxygen flow ratio show a better crystallinity. Static magnetic measurement results indicated that the saturation magnetization of the films was greatly affected by the crystallinity, grain dimension, and cation distribution in the NiZn-ferrite films. The NiZn-ferrite thin films with a maximum saturation magnetization of 151 emucm-3, which is about 40% of the bulk NiZn ferrite, was obtained under relative oxygen flow ratio of 60%.


2010 ◽  
Vol 1260 ◽  
Author(s):  
Sanjeev K. Nayak ◽  
Heike C. Herper ◽  
Peter Entel

AbstractTransition metals doped ZnO are possible candidates for multiferroics. Here, we have investigated the evolution of ferromagnetism due to Co dopants. The magnetic properties have been studied for Co concentrations from 0 to 100% by using ab-initio methods, i.e., KKR Green's function techniques. In order to estimate the Curie temperature we have performed Monte Carlo simulations with ab-initio calculated exchange parameters.From our calculations the onset of ferromagnetism occurs between 5 to 20% of Co depending on the numerical details of KKR method used. For Co concentrations larger than 50% the system is dominated by antiferromagnetic coupling and no Curie temperature can be obtained.


2011 ◽  
Vol 687 ◽  
pp. 500-504
Author(s):  
S. X. Xue ◽  
S.S. Feng ◽  
P. Y. Cai ◽  
Q T Li ◽  
H. B. Wang

Ni54Mn21-xFexGa25(x=0,1,3,5,7,9)polycrystalline alloys were prepared by the technique of directional solidification and the effect of substituting Fe for Mn on the martensitic transformation and mechanical properties of the alloys was analyzed. It was found that the Curie temperature increased with increasing substitution while the martensitic transformation temperature decreased. The Fe-doped Ni54Mn21Ga25 alloys exhibit excellent magnetic properties at room temperature; the typical Ni54Mn20Fe1Ga25 alloy shows a large magnetic-induced-strain of -1040 ppm at a magnetic field of 4000 Oe.


2000 ◽  
Vol 77 (9) ◽  
pp. 731-736
Author(s):  
H Atmani ◽  
S Grognet ◽  
J Teillet ◽  
K Zellama ◽  
R Zuberek

Nitriding thermochemical treatment under suitable parameters is used to nano-crystallize Fe73.5Cu1Nb3Si13.5B9 ribbon. This new kind of treatment leads to finer nano-structure and modifies the structural parameters of the α-Fe(Si) phase, obtained during the treatment. The magnetic properties are also improved; specific magnetization at room temperature and Curie temperature of the crystalline phase increase, and the magnetostriction constant becomes smaller. The nitrogenation seems to offer a new way to obtain nanostructured ribbons. PACS No.: 75.70


2012 ◽  
Vol 29 (1) ◽  
pp. 50
Author(s):  
D.N Ba ◽  
L.T Tai ◽  
N.T Trung ◽  
N.T Huy

The influences of the substitution of Ni with Mg on crystallographic and magnetic properties of the intermetallic alloys LaNi5-xMgx (x ≤ 0.4) were investigated. The X-ray diffraction patterns showed that all samples were of single phase, and the lattice parameters, a and c, decreased slightly upon chemical doping. LaNi5 is well known as an exchange-enhanced Pauli paramagnet. Interestingly, in LaNi5-xMgx, the ferromagnetic order existed even with a small amount of dopants; the Curie temperature reached the value of room temperature for x = 0.2, and enhanced with increasing x.


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