Masamichi Nishino

Realization of the mean-field universality class in spin-crossover materials (2007)

Miyashita, Seiji, Konishi, Yusuké, Nishino, Masamichi, Tokoro, Hiroko, Rikvold, Per Arne

In spin-crossover materials, the volume of a molecule changes depending on whether it is in the high-spin (HS) or low-spin (LS) state. This change causes distortion of the lattice. Elastic...

Monte Carlo simulation of pressure-induced phase transitions in spin-crossover materials (2007)

Konishi, Yusuke, Tokoro, Hiroko, Nishino, Masamichi, Miyashita, Seiji

Pressure-induced phase transitions of spin-crossover materials were simulated by a Monte Carlo simulation in the constant pressure ensemble for the first time. Here, as the origin of the cooperative...

Simple Two-Dimensional Model for the Elastic Origin of Cooperativity among Spin States of Spin-Crossover Complexes (2007)

Nishino, Masamichi, Boukheddaden, Kamel, Konishi, Yusuké, Miyashita, Seiji

We study the origin of the cooperative nature of spin crossover (SC) between low spin (LS) and high spin (HS) states from the view point of elastic interactions among molecules. As the size of each...

Structure of Metastable States in Phase Transitions with High-Spin Low-Spin Degree of Freedom (2005)

Miyashita, Seiji, Konishi, Yusuke, Tokoro, Hiroko, Nishino, Masamichi, Boukheddaden, Kamel, Varret, Francios

Difference of degeneracy of the low-spin (LS) and high-spin (HS) states causes interesting entropy effects on spin-crossover phase transitions and charge transfer phase transitions in materials...

A Unified Theoretical Description of the Thermodynamical Properties of Spin Crossover with Magnetic Interactions (2005)

Boukheddaden, Kamel, Nishino, Masamichi, Miyashita, Seiji, Varret, Francois

After the discovery of the phenomena of light-induced excited spin state trapping (LIESST), the functional properties of metal complexes have been studied intensively. Among them, cooperative...

Dynamical Aspects of Photoinduced Magnetism and Spin-Crossover phenomena in Prussian Blue Analogs (2005)

Nishino, Masamichi, Boukheddaden, Kamel, Miyashita, Seiji, Varret, Francois

We present dynamical properties of spin crossover compounds with photomagnetization, proposing a new model in which the spin-crossover phenomena and magnetic ordering are incorporated in a unified...

Noise effect on the nonadiabatic transition and correction to the tunneling energy gap estimated by the Landau-Zener-Stuckelberg formula (2001)

Nishino, Masamichi, Saito, Keiji, Miyashita, Seiji

We study effect of noise on the tunneling process of the magnetization in a sweeping field from the viewpoint of the nonadiabatic transition. The tunneling probability depends on the properties of...

Dynamical process for switching dynamics between metastable ordered magnetic state and nonmagnetic ground state in photoinduced phase transition (2000)

Nishino, Masamichi, Miyashita, Seiji

We propose a dynamical mechanism of the two-way switching between the metastable state and the stable state, which has been found in experiments of photoinduced reversible magnetization and...

Local magnetic structure due to inhomogeneity of interaction in S=1/2 antiferromagnetic chain (1999)

Nishino, Masamichi, Onishi, Hiroaki, Roos, Pascal, Yamaguchi, Kizashi, Miyashita, Seiji

We study the magnetic properties of $S=1/2$ antiferromagnetic Heisenberg chains with inhomogeneity of interaction. Using a quantum Monte Carlo method and an exact diagonalization method, we study...

Quantum Monte Carlo Study on Magnetization Processes (1999)

Onishi, Hiroaki, Nishino, Masamichi, Kawashima, Naoki, Miyashita, Seiji

A quantum Monte Carlo method combining update of the loop algorithm with the global flip of the world line is proposed as an efficient method to study the magnetization process in an external field,...

Switching dynamics between metastable ordered magnetic state and nonmagnetic ground state - A possible mechanism for photoinduced ferromagnetism - (1998)

Nishino, Masamichi, Yamaguchi, Kizashi, Miyashita, Seiji

By studying the dynamics of the metastable magnetization of a statistical mechanical model we propose a switching mechanism of photoinduced magnetization. The equilibrium and nonequilibrium...