scholarly journals Metamagnetism in manganate magnesium ferrite

2019 ◽  
Vol 70 (1) ◽  
pp. 78-81
Author(s):  
Jozef Sláma ◽  
Jozef Pal’a ◽  
Martin Šoka ◽  
Jan Lokaj
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Low Temperatures ◽  
Unit Cell Volume ◽  
Magnetic Phase ◽  
Critical Transition ◽  
Magnesium Ferrite ◽  
Spin Ordering ◽  
Transition Field ◽  
Manganese Magnesium

Abstract The metamagnetic properties of the manganese magnesium ferrites having the general formula Mn0.7Mg0.3Fe2O4 prepared by the standard ceramic technique have been studied. It is proposed that when a change of temperature at adequate magnetic field is applied in a Mn0.7Mg0.3Fe2O4 a magnetic phase transition will be generated, giving rise to an antiferromagnetic (AFM) state from ferrimagnetic (FM) phase. The critical transition field Hac = 300 A/m was estimated for critical magnetization curve of transition from the metamagnetic behavior to FM behavior of sample. The FM to AFM transition in these ferrites is accompanied by a Néel type to Yafet-Kittel type transition and gradual spin ordering changes of the unit cell volume. The application of an external magnetic field to the low-temperatures AFM state causes the sample to reset to the original FM state.

ACOUSTIC PROPERTIES OF Nd2CuO4 AT LOW TEMPERATURES

1991 ◽  
Vol 05 (20) ◽  
pp. 1367-1375 ◽  
Author(s):  
V. D. FIL ◽  
G. A. ZVYAGINA ◽  
S. V. ZHERLITSYN ◽  
I. M. VITEBSKY ◽  
V. L. SOBOLEV ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Low Temperatures ◽  
Acoustic Properties ◽  
Continuous Spin ◽  
Magnetic Subsystem ◽  
Magnetoelastic Coupling ◽  
Ferroelastic Phase Transition

Acoustic properties anomalies near the points of phase transition in the magnetic subsystem of Nd 2 CuO 4 have been studied. A spontaneous ferroelastic phase transition at T = 5 K and magnetic field induced ferroelastic phase transition (PT) associated with continuous spin reorientations at T < 0.5 K have been found. The exchange nature of magnetoelastic coupling is suggested.

Magnetic Properties and Phase Diagram of Quasi-two-dimensional Na2Co2TeO6 Single Crystal Under High Magnetic Field

2021 ◽  
Author(s):  
Guiling Xiao ◽  
Zhengcai Xia ◽  
Yujie Song ◽  
Lixia Xiao
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Diagram ◽  
Magnetic Phase ◽  
Magnetic Coupling ◽  
Experimental Results ◽  
Antiferromagnetic Coupling ◽  
Magnetic Field Direction ◽  
Antiferromagnetic Ordering ◽  
The Magnetic Field

Abstract We investigated the magnetic characteristics of Na2Co2TeO6 at different temperatures and magnetic field. The experimental results indicated that the magnetic field can disturb the antiferromagnetic interaction and lead to the disorder. Magnetization curves measured with different angles θ (θ is between the magnetic field direction and c axis) express the magnetocrystalline anisotropy in this system. when the angle θ=0 (magnetic field parallel to c axis), two continuous magnetic phase transitions at critical temperature TN1 and TN3 were observed. As θ changes, TN1 is almost independent on θ, indicating the magnetic ordering at TN1 was a spontaneous behavior with a robust AFM characteristic. On the other hand, as θ increases from 0 to 180, TN3 presents extreme value at θ=90 (magnetic field perpendicular to c axis). It indicates that TN3 were sensitive to temperature and magnetic fields. At some angles closing to ab plane, an additional phase transition was observed at TN2. This phase transition at TN2 may mainly result from the long range antiferromagnetic ordering within ab-plane. Furthermore, the magnetization measurement up to 50 T revealed the strong antiferromagnetic coupling in the system, and in which the magnetic coupling within the honeycomb layers is strong and the magnetic coupling interaction between honeycomb layers is weaker. Based on the experimental results, we have obtained the complete magnetic phase diagram.

Resistive Anomaly Relevant to Nd Moments in the Antiferromagnetic Phase of the Bandwidth-Controlled Manganites

2000 ◽  
Vol 658 ◽  
Author(s):  
H. Kuwahara ◽  
K. Noda ◽  
R. Kawasaki
Keyword(s):  
Phase Transition ◽  
Low Temperatures ◽  
Magnetic Phase ◽  
Magnetic Moments ◽  
Zeeman Effect ◽  
Parent Compound ◽  
Spin Valve ◽  
Level Crossing ◽  
Monotonically Decrease ◽  
Moment State

ABSTRACTWe have investigated the electronic and magnetic properties of (Nd1−ySmy)0.45Sr0.55MnO3(0≤y≤1) crystals, in which one-electron bandwidth (W ) is systematically decreased from the parent compound (y=0) with increase of y. We have found remarkable magnetic phase transition concerning the change of rare-earth (RE) moments in low temperatures below 25 K. The subtle drop in resistivity superimposed upon the spin-valve like magnetoresistance (MR) was observed for the isothermal MR measurements, e.g. δρ(H)|ρ(H')≍4.7% at 3.5 T and 4 K. The phase transition fields corresponding to these concomitant magnetic and resistive changes monotonically decrease with temperature and disappear above ∼25 K. It turned out that the resistive drop is due to the field-induced increase of magnetic moments ofRE ions from magnetization measurements. The field-induced phase transition from the small moment state to the large one in RE ions can be explained in terms of energy level crossing between the crystal-field-split J multiplets by the Zeeman effect.

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