Anomalies of Elastic Properties at Phase Transitions in Rare Earth Cobaltites RBaCo4O7 (R = Y, Er - Lu)

2012 ◽  
Vol 190 ◽  
pp. 482-485 ◽  
Author(s):  
Z.A. Kazei ◽  
V.V. Snegirev ◽  
L.P. Kozeeva ◽  
M.Yu. Kameneva
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Rare Earth ◽  
Transition Temperature ◽  
Elastic Properties ◽  
Magnetic Phase ◽  
Structural Phase ◽  
Exchange Interactions ◽  
Temperature Decrease ◽  
Low Dimension

Elastic properties of rare-earth cobaltites RBaCo4O7 (R = Y, Er - Lu) are studied in the temperature range (4.2 - 300) K. Significant softening of Youngs modulus for Lu-and Yb-cobaltites is found at temperature decrease, showing an instability of the crystal structure and accompanying by a reverse jump at the structural phase transition. Softening and jump at phase transition decrease more than by the order of value, while the transition temperature Ts and hysteresis dTs enlarge from Lu-to Tm-and Er-compounds. Smooth and weak elastic anomaly at the magnetic phase transition is found resulting from low dimension and frustration of exchange interactions in the Co subsystem in most of the rare-earth cobaltites studied.

scholarly journals Manifestation of magnetoelastic interactions in Raman spectra of HoxNd1−xFe3(BO3)4 crystals

2018 ◽  
Vol 08 (02) ◽  
pp. 1850011 ◽  
Author(s):  
A. S. Krylov ◽  
S. N. Sofronova ◽  
I. A. Gudim ◽  
S. N. Krylova ◽  
Rajesh Kumar ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectra ◽  
Structural Phase Transition ◽  
Solid Solutions ◽  
Order Parameter ◽  
Soft Mode ◽  
Magnetic Phase ◽  
Structural Phase ◽  
Exchange Interactions ◽  
Magnetoelastic Interaction

Raman spectra of Ho[Formula: see text]NdxFe(BO3)4 ([Formula: see text], 0.75, 0.5, 0.25) have been studied in temperature range 10–400[Formula: see text]K. Two compositions ([Formula: see text], [Formula: see text]) demonstrate structural phase transition with soft mode restoration. The addition of Nd atoms increases interatomic spacing and decreases the temperature of structural phase transition. The solid solutions ([Formula: see text], 0.5, 0.25) demonstrate the emergence of the peaks corresponding to magnetoelastic interaction below Néel temperature. The order parameter of the magnetic phase transition has been determined. The equal concentrations of holmium and neodymium atoms prevent magnon soft modes condensation caused by exchange interactions in Fe–O–Fe chains are observed. Calculations confirm the data obtained in the experiment.

Deuterium substitution effects on the structural and magnetic phase transitions of a hydrogen-bonded coordination polymer, bis(glycolato)copper(ii)

2016 ◽  
Vol 45 (42) ◽  
pp. 16774-16778 ◽  
Author(s):  
Shota Yoneyama ◽  
Takeshi Kodama ◽  
Koichi Kikuchi ◽  
Takumi Fujisawa ◽  
Akira Yamaguchi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Magnetic Phase ◽  
Structural Phase ◽  
Magnetic Phase Transitions ◽  
Substitution Effects ◽  
Hydroxyl Groups ◽  
Large Shift ◽  
Deuterium Substitution

Bis(glycolato)copper(ii) [Cu(HOCH2CO2)2] shows a large shift of the structural phase transition temperature by deuterium substitution of the hydroxyl groups in it.

Structural phase transition and elastic properties of rare earth nitrides

2010 ◽  
Vol 84 (9) ◽  
pp. 1183-1192 ◽  
Author(s):  
Aditi Rukmangad ◽  
Mahendra Aynyas ◽  
Sankar P. Sanyal
Keyword(s):  
Phase Transition ◽  
Rare Earth ◽  
Elastic Properties ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Rare Earth Nitrides

Peculiarities of Elastic Properties of RE Cobaltites RBaCo4O7 (R = Dy - Er, Y) at Magnetic Phase Transitions

2015 ◽  
Vol 233-234 ◽  
pp. 145-148 ◽  
Author(s):  
Zoya Kazei ◽  
Vyacheslav Snegirev ◽  
Alexander Andreenko ◽  
Ludmila Kozeeva ◽  
Margarita Kameneva
Keyword(s):  
Phase Transition ◽  
Rare Earth ◽  
Young’S Modulus ◽  
Magnetic Phase Transition ◽  
Magnetic Phase ◽  
Young's Modulus ◽  
Exchange Interactions ◽  
Magnetic Phase Transitions ◽  
Wide Range ◽  
Irreversible Effects

It has been found that the temperature dependences of the Young’s modulus for rare-earth cobaltites RBaCo4O7 (R = Dy - Er, Y) exhibit significant hysteresis and irreversible effects over a wide range (80–280) K between the structural and magnetic phase transition temperatures. At the magnetic phase transition temperature, there are weak and smoothed anomalies of the Young’s modulus, which correlate with the low dimensionality and frustration of the exchange interactions in the Kagome lattice of the Co subsystem for the studied rare-earth cobaltites.

scholarly journals Study of physical properties of a ferrimagnetic spinel Cu1.5Mn1.5O4: spin dynamics, magnetocaloric effect and critical behavior

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25664-25676
Author(s):  
Abir Hadded ◽  
Jalel Massoudi ◽  
Sirine Gharbi ◽  
Essebti Dhahri ◽  
A. Tozri ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Physical Properties ◽  
Magnetocaloric Effect ◽  
Phase Transition Temperature ◽  
Magnetic Phase Transition ◽  
Critical Behavior ◽  
Magnetic Phase ◽  
Spin Dynamics ◽  
Critical Behaviour

The present work reports a detailed study of the spin dynamics, magnetocaloric effect and critical behaviour near the magnetic phase transition temperature, of a ferrimagnetic spinel Cu1.5Mn1.5O4.

scholarly journals Elastic Properties and Energy Loss Related to the Disorder–Order Ferroelectric Transitions in Multiferroic Metal–Organic Frameworks [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3]

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3125
Author(s):  
Zhiying Zhang ◽  
Hongliang Yu ◽  
Xin Shen ◽  
Lei Sun ◽  
Shumin Yue ◽  
...  
Keyword(s):  
Phase Transition ◽  
Energy Loss ◽  
Elastic Properties ◽  
Ferroelectric Phase ◽  
Loss Modulus ◽  
Structural Phase ◽  
Metal Organic Frameworks ◽  
First Order ◽  
Metal Organic ◽  
Elastic Anomalies

Elastic properties are important mechanical properties which are dependent on the structure, and the coupling of ferroelasticity with ferroelectricity and ferromagnetism is vital for the development of multiferroic metal–organic frameworks (MOFs). The elastic properties and energy loss related to the disorder–order ferroelectric transition in [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3] were investigated using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The DSC curves of [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3] exhibited anomalies near 256 K and 264 K, respectively. The DMA results illustrated the minimum in the storage modulus and normalized storage modulus, and the maximum in the loss modulus, normalized loss modulus and loss factor near the ferroelectric transition temperatures of 256 K and 264 K, respectively. Much narrower peaks of loss modulus, normalized loss modulus and loss factor were observed in [(CH3)2NH2][Mg(HCOO)3] with the peak temperature independent of frequency, and the peak height was smaller at a higher frequency, indicating the features of first-order transition. Elastic anomalies and energy loss in [NH4][Mg(HCOO)3] near 256 K are due to the second-order paraelectric to ferroelectric phase transition triggered by the disorder–order transition of the ammonium cations and their displacement within the framework channels, accompanied by the structural phase transition from the non-polar hexagonal P6322 to polar hexagonal P63. Elastic anomalies and energy loss in [(CH3)2NH2][Mg(HCOO)3] near 264 K are due to the first-order paraelectric to ferroelectric phase transitions triggered by the disorder–order transitions of alkylammonium cations located in the framework cavities, accompanied by the structural phase transition from rhombohedral R3¯c to monoclinic Cc. The elastic anomalies in [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3] showed strong coupling of ferroelasticity with ferroelectricity.

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