Specific Features of Jahn-Teller Structure Phase Transitions in Nanocrystalline Materials

Specific features of the structural phase transitions of the first order were investigated in nanosized crystals with Jahn-Teller ions. As an example the phase transitions of martensite type with changes in symmetry from a cubic to a tetragonal one have been considered. The Kanamori model was used to take into account the size of nanocrystallites and the distribution of cations over non-equivalent crystallographic sublattices in such systems. It was shown the temperature and the latent heat of the transition decrease significantly for the nanoscaled grains. A possibility of multi-phase state for nanocrystalline materials was considered.

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Neutron diffraction evidence for kinetic arrest of first order magneto-structural phase transitions in some functional magnetic materials

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/25/49/496011 ◽

2013 ◽

Vol 25 (49) ◽

pp. 496011 ◽

Cited By ~ 17

Author(s):

V Siruguri ◽

P D Babu ◽

S D Kaushik ◽

Aniruddha Biswas ◽

S K Sarkar ◽

...

Keyword(s):

Phase Transitions ◽

Neutron Diffraction ◽

Magnetic Materials ◽

Structural Phase ◽

Structural Phase Transitions ◽

First Order ◽

Kinetic Arrest

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First-order magnetic and structural phase transitions inFe1+ySexTe1−x

Physical Review B ◽

10.1103/physrevb.79.054503 ◽

2009 ◽

Vol 79 (5) ◽

Cited By ~ 434

Author(s):

Shiliang Li ◽

Clarina de la Cruz ◽

Q. Huang ◽

Y. Chen ◽

J. W. Lynn ◽

...

Keyword(s):

Phase Transitions ◽

Structural Phase ◽

Structural Phase Transitions ◽

First Order

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Phase and Structural Behaviour in the NdAlO3-EuAlO3 System

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.200.93 ◽

2013 ◽

Vol 200 ◽

pp. 93-99 ◽

Cited By ~ 3

Author(s):

Natalia Ohon ◽

Leonid Vasylechko ◽

Yurii Prots ◽

Marcus Schmidt ◽

Caroline Curfs

Keyword(s):

Phase Diagram ◽

Phase Transitions ◽

Binary System ◽

Solid Solutions ◽

Room Temperature ◽

Structural Phase ◽

Structural Phase Transitions ◽

Structural Behaviour ◽

First Order

Phase and structural behaviour in the NdAlO3–EuAlO3 system has been studied in the whole concentration range. Depending on x two kinds of solid solutions Nd1‑xEuxAlO3 exist at room temperature: one with rhombohedral (x < 0.15) and one with orthorhombic (x≈ 0.15–0.20, where the co-existence of both phases was observed. First-order structural phase transitions Pbnm↔Rc has been detected in Nd1-xEuxAlO3 with x = 0.3, 0.4, 0.6 at 520 K, 627 K and 988 K, respectively. Based on the experimental and literature data, the phase diagram of the pseudo-binary system NdAlO3–EuAlO3 has been constructed.

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Influence of Defects on First Order Structural Phase Transitions

Phase Transitions ◽

10.1080/0141159031000081060 ◽

2003 ◽

Vol 76 (3) ◽

pp. 253-259 ◽

Cited By ~ 2

Author(s):

A.P. Levanyuk

Keyword(s):

Phase Transitions ◽

Structural Phase ◽

Structural Phase Transitions ◽

First Order

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Structures, Phase Transitions and Tricritical Behavior of the Hybrid Perovskite Methyl Ammonium Lead Iodide

Scientific Reports ◽

10.1038/srep35685 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 212

Author(s):

P. S. Whitfield ◽

N. Herron ◽

W. E. Guise ◽

K. Page ◽

Y. Q. Cheng ◽

...

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Structural Phase ◽

Photovoltaic Performance ◽

Orthorhombic Phase ◽

Structural Phase Transitions ◽

Lead Iodide ◽

First Order ◽

Hybrid Perovskite ◽

The Impact

Abstract We have examined the crystal structures and structural phase transitions of the deuterated, partially deuterated and hydrogenous organic-inorganic hybrid perovskite methyl ammonium lead iodide (MAPbI3) using time-of-flight neutron and synchrotron X-ray powder diffraction. Near 330 K the high temperature cubic phases transformed to a body-centered tetragonal phase. The variation of the order parameter Q for this transition scaled with temperature T as Q ∼ (Tc−T)β, where Tc is the critical temperature and the exponent β was close to ¼, as predicted for a tricritical phase transition. However, we also observed coexistence of the cubic and tetragonal phases over a range of temperature in all cases, demonstrating that the phase transition was in fact first-order, although still very close to tricritical. Upon cooling further, all the tetragonal phases transformed into a low temperature orthorhombic phase around 160 K, again via a first-order phase transition. Based upon these results, we discuss the impact of the structural phase transitions upon photovoltaic performance of MAPbI3 based solar cells.

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