scholarly journals Magnetic and Martensitic Transitions in Ni2Mn1+xSn1-x Alloys

2009 ◽  
Vol 635 ◽  
pp. 97-102 ◽  
Author(s):  
Subham Chatterjee ◽  
S. Majumdar
Keyword(s):  
Ground State ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Magnetic Interactions ◽  
Martensitic Transition ◽  
Magnetic Ground State ◽  
First Order ◽  
Saturation Moment ◽  
High Fields ◽  
Curie Temperature Tc

The magnetic phase diagram of Ni2Mn1+xSn1−x based ferromagnetic (FM) shape memory alloys for varied concentrations of x have been studied. With increasing concentration of Mn, the FM Curie temperature (TC) decreases, while the martensitic transition temperature (TM) goes higher. For x = 0.44 and 0.48, TM is close to the onset of ferromagnetism, and two distinct magnetic transitions are observed corresponding to the TC’s of the FM phases of martensite and austenite respectively. The isothermal magnetization at 5 K indicates saturating behaviour at high fields and the saturation moment drops linearly with x. The samples show reasonably large negative magnetoresistance around TM, however the magnitude drops with increasing x. The magnetoresistance is found to be highly irreversible with respect to the applied magnetic field and field induced arrested state is observed for all the FM samples studied around the first order martensitic transition. The present investigation clearly indicates complex magnetic ground state of the Ni2Mn1+xSn1−x samples with competing magnetic interactions.

scholarly journals Pressure Effects on the Magnetic Phase Diagram of the CeNMSb2 (NM: Au and Ag): A DFT Study

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2237
Author(s):  
Mowafaq Mohammad Alsardia ◽  
Jaekyung Jang ◽  
Joo Yull Rhee
Keyword(s):  
Ground State ◽  
Noble Metals ◽  
Easy Axis ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Pressure Effects ◽  
Spin Orbit ◽  
Magnetic Ground State ◽  
Magnetic Easy Axis ◽  
Spin Orbit Interactions

We explore the influence of pressure on the magnetic ground state of the heavy-fermion antiferromagnet (ferromagnet) CeAuSb 2 (CeAgSb 2 ) using first-principles calculations. The total-energy differences obtained by including the spin-orbit interactions and the on-site Coulomb potential for the Ce-derived 4f-orbitals are necessary to realize the accurate magnetic ground state of CeNMSb 2 (NM: Au and Ag). According to our results, the appearance of a new magnetic phase of CeAuSb 2 (CeAgSb 2 ) at the pressure of 2.1 GPa (3.5 GPa) is due to the rotation of the magnetic easy axis from the <001> to the <100> direction. Additionally, our data confirm that CeAgSb 2 is antiferromagnetic (AFM) above a critical pressure P c , and such a tendency is expected for CeAuSb 2 and remains to be seen. Through the spin-orbit-coupling Hamiltonian and detailed information on the occupation of individual 4f-orbitals of the Ce atom obtained by the electronic-structure calculations, we can deduce the rotation of the magnetic easy axis upon the application of pressure. According to the present and previous studies, the differences among the magnetic properties of CeNMSb 2 (NM: Cu, Ag and Au) compounds are not due to the different noble metals, but due to the subtle differences in the relative position of Ce atoms and, in turn, different occupations of Ce 4f-orbitals.

scholarly journals Quadrupolar susceptibility and magnetic phase diagram of PrNi2Cd20 with non-Kramers doublet ground state

2020 ◽  
Vol 100 (10) ◽  
pp. 1268-1281
Author(s):  
Tatsuya Yanagisawa ◽  
Hiroyuki Hidaka ◽  
Hiroshi Amitsuka ◽  
Shintaro Nakamura ◽  
Satoshi Awaji ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Ground State ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Doublet Ground State ◽  
Kramers Doublet

MAGNETIC PHASE TRANSITIONS IN Ce(Fe1–xCox)2 SYSTEM

1993 ◽  
Vol 07 (01n03) ◽  
pp. 822-825 ◽  
Author(s):  
NAUSHAD ALI ◽  
XIANFENG ZHANG
Keyword(s):  
Phase Transitions ◽  
Magnetic Phase ◽  
Ac Susceptibility ◽  
Magnetic Phase Diagram ◽  
Ferromagnetic State ◽  
Magnetic Phase Transitions ◽  
Itinerant Electron ◽  
Electron Systems ◽  
First Order ◽  
First Order Transition

Re-entrant magnetic phase transitions in Ce(Fe1–xMx)2 systems (where M=Al, Ru, Co, etc.) are being investigated by various research groups. It has been observed that the system goes from a paramagnetic to ferromagnetic state followed by an almost complete loss of magnetization as the temperature is lowered. We have done systematic experimental measurements of magnetization, ac susceptibility, electrical resistivity, and thermal expansion on the Ce(Fe1–xCox)2 system. It is found that as the temperature is decreased, the system goes from para- to ferro- to antiferro-magnetic phase. The ferro- to antiferro-magnetic phase transition is a first order transition. Our experimental results are consistent with the magnetic phase diagram predictions by Moriya and Usami's theory of strongly interacting itinerant electron systems.

scholarly journals Incommensurate Spin-Density Wave in Two-Dimensional Hubbard Model

2012 ◽  
Vol 190 ◽  
pp. 67-70 ◽  
Author(s):  
M.A. Timirgazin ◽  
Anatoly K. Arzhnikov ◽  
A.V. Vedyayev
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
Magnetic Phase ◽  
Density Wave ◽  
Spin Density Wave ◽  
Magnetic Phase Diagram ◽  
Two Dimensional ◽  
Magnetic Phases ◽  
Model Relation

We consider the magnetic phase diagram of the two-dimensional Hubbard model ona square lattice.We take into account both spiral and collinear incommensurate magnetic states.The possibility of phase separation of spiral magnetic phases is taken into consideration as well.Our study shows that all the listed phases appear to be the ground state at certain parametersof the model. Relation of the obtained results to real materials, e.g. Cu-based high-temperaturesuperconductors, is discussed.

Magnetoelectric Coupling on the Fused Azulene Oligomers

2021 ◽  
Author(s):  
Alexandra Valentim ◽  
Daniel J. Garcia ◽  
João A. Plascak
Keyword(s):  
Phase Diagram ◽  
Ground State ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Coulomb Repulsion ◽  
Magnetoelectric Coupling ◽  
Multiferroic Materials ◽  
Hubbard Hamiltonian ◽  
Higher Spin ◽  
Boundary Lines

<div><div><div><p>The global magnetic phase diagram for fused azulene oligomers is obtained by using a fermionic Hubbard Hamiltonian, a intermediate model between the molecular (Pariser-Parr-Pople empiric Hamiltonian) and spin-1/2 antiferromagnetic Heisenberg approaches. As a function of the on-site coulomb repulsion and the oligomer size we show that fused azulene transitions from a singlet (S = 0) to a higher-spin (S = 1, 2, 3) ground state. Near the quantum magnetic phase transition the electric dipole moment, present on fused azulene molecules, couples with the magnetic moment leading to a divergent magnetoelectric susceptibility at the boundary lines of the magnetic phase diagram. These spontaneous electric and magnetic polarizations, together with the magnetoelectric coupling between them, indicate that fuzed azulene molecules are potentially strong candidates for purely organic multiferroic materials.</p></div></div></div>

Magnetoelectric Coupling on the Fused Azulene Oligomers

2021 ◽  
Author(s):  
Alexandra Valentim ◽  
Daniel J. Garcia ◽  
João A. Plascak
Keyword(s):  
Phase Diagram ◽  
Ground State ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Coulomb Repulsion ◽  
Magnetoelectric Coupling ◽  
Multiferroic Materials ◽  
Hubbard Hamiltonian ◽  
Higher Spin ◽  
Boundary Lines

<div><div><div><p>The global magnetic phase diagram for fused azulene oligomers is obtained by using a fermionic Hubbard Hamiltonian, a intermediate model between the molecular (Pariser-Parr-Pople empiric Hamiltonian) and spin-1/2 antiferromagnetic Heisenberg approaches. As a function of the on-site coulomb repulsion and the oligomer size we show that fused azulene transitions from a singlet (S = 0) to a higher-spin (S = 1, 2, 3) ground state. Near the quantum magnetic phase transition the electric dipole moment, present on fused azulene molecules, couples with the magnetic moment leading to a divergent magnetoelectric susceptibility at the boundary lines of the magnetic phase diagram. These spontaneous electric and magnetic polarizations, together with the magnetoelectric coupling between them, indicate that fuzed azulene molecules are potentially strong candidates for purely organic multiferroic materials.</p></div></div></div>

Magnetic phase diagram of UNi2Si2 in high fields

2000 ◽  
Vol 276-278 ◽  
pp. 686-687 ◽  
Author(s):  
P Svoboda ◽  
P Javorský ◽  
V Sechovský ◽  
A.A Menovsky
Keyword(s):  
Phase Diagram ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
High Fields
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