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Personal Information

Dr Masahiko Isobe

Institute for Solid State Physics, University of Tokyo
Kashiwanoha, Kashiwa-shi, Chiba 277-8581, Japan.

phone & fax: 81-4-7136-3499
e-mail: isobe [at] issp.u-tokyo.ac.jp

Research interests

Our general interests are in solid state physics and chemistry of early transition metal oxides.

Vanadium oxides

α’-NaV₂O₅ : novel charge order system !?
CaV₂O₅ : two-leg spin ladder system
γ-LiV₂O₅ : S = 1/2 quasi 1D system
MgV₂O₅ : two-leg spin ladder system
Na₉V₁₄O₃₅ : 2D spin gap system
β-Sr_0.33V₂O₅, β-Ca_0.33V₂O₅ : charge order system
K₂V₈O₁₆, Rb₂V₈O₁₆ : metal-insulator transition (charge ordering ?!)
( RbVO₃, CsVO₃ : white-light-emitting device )

Titanium oxieds

NaTiSi₂O₆ : orbital-driven Peierls transition!?
MgTi₂O₄ : metal-insulator transition (orbital ordering ?!)

Chromium oxieds

CaCrO₃ : antiferromagnetic metallic oxide
K₂Cr₈O₁₆ : ferromagnetic metal (or half-metal) to insulator transition

Selected publications:

	Vanadium Oxides
	"Magnetic susceptibility of quasi-one-dimensional compound NaV₂O₅- Possible spin-Peierls compound with high critical temperature of 34K-", M. Isobe and Y. Ueda, J Phys Soc Jpn 65 (1996) 1178-1181. "Crystal growth of new spin-Peierls compound NaV₂O₅.", M. Isobe, C. Kagami and Y. Ueda, J Crystal Growth 181 (1997) 314-317. "Effect of Na-deficiency on the spin-Peierls transition in NaV₂O₅", M. Isobe and Y. Ueda, J Alloys Compds 262 (1997) 180-184. "Observation of a spin gap in MgV₂O₅ from high field magnetization measurements", M. Isobe, Y. Ueda, K. Takizawa and T. Goto, J Phys Soc Jpn 67 (1998) 755-758. "Crystal growth and magnetic properties of Li_xV₂O₅ (0.90 <= x <= 100)", M. Isobe and Y. Ueda, Mater Res Bull 34 (1999) 1719-1728. "Crystal structure and magnetic properties of Na₉V₁₄O₃₅: Sodium-vanadium bronze NaxV₂O₅", M. Isobe, Y. Ueda, Y. Oka and T. Yao, J Solid State Chem 145 (1999) 361-365. "Physical properties of vanadium oxide bronzes A_0.33V₂O₅ (A = Ca and Sr)", M. Isobe and Y. Ueda, Mol Cryst Liq Cryst 341 (2000) 1075-1080. "Observation of Metal-Insulator Transition in Hollandite Vanadate, K₂V₈O₁₆", M. Isobe, S. Koishi, N. Kouno, J. Yamaura, T. Yamauchi, H. Ueda, H. Goto, T. Yagi and Y. Ueda, J Phys Soc Jpn 75 (2006) 073801 "Direct fabrication of metavanadate phosphor films on organic substrates for white-light-emitting devices", T. Nakajima, M. Isobe, T. Tsuchiya, Y. Ueda and T. Kumagai, Nat. Mater. 7 (2008) 735-740. "Dimerization and Charge Order in Hollandite K₂V₈O₁₆", A. C. Komarek, M. Isobe, J. Hemberger, D. Meier, T. Lorenz, D. Trots, A. Cervellino, M. T. Fernandez-Diaz, Y. Ueda, and M. Braden, Phys. Rev. Lett. 107 (2011) 027201-1-4.
	Titanuim Oxieds
	"Novel phase transition in spin-1/2 linear chain systems: NaTiSi₂O₆ and LiTiSi₂O₆", M. Isobe, E. Ninomiya, A. N. Vasil'ev and Y. Ueda, J Phys Soc Jpn 71 (2002) 1423-1426. "Observation of phase transition from metal to spin-singlet insulator in MgTi₂O₄ with S=1/2 pyrochlore lattice", M. Isobe and Y. Ueda, J Phys Soc Jpn 71 (2002) 1848-1851. "Observation of lattice dimerization in spin-singlet low temperature phase of NaTiSi₂O₆", E. Ninomiya, M. Isobe, Y. Ueda, M. Nishi, K. Ohoyama, H. Sawa and T. Ohama, Physica B 329 (2003) 884-885. "Synthesis, structure and physical properties of spinel solid solutions Mg₂TiO₄-MgTi₂O₄", M. Isobe and Y. Ueda, J Alloys Compds 383 (2004) 85-88.
	Chromium Oxieds
	"CaCrO₃: An Anomalous Antiferromagnetic Metallic Oxide", A. C. Komarek, S. V. Streltsov, M. Isobe, T. Moller, M. Hoelzel, A. Senyshyn, D. Trots, M. T. Fernandez-Diaz, T. Hansen, H. Gotou, T. Yagi, Y. Ueda, V. I. Anisimov, M. Grueninger, D. I. Khomskii, M. Braden, Phys. Rev. Lett. 101 (2008) 167204-1-4. "Discovery of ferromagnetic-half-metal-to-insulator transition in K₂Cr₈O₁₆", K. Hasegawa, M. Isobe, T. Yamauchi, H. Ueda, J. Yamaura, H. Gotou, T. Yagi, H. Sato and Y. Ueda, Phys. Rev. Lett. 103(2009)146403-1-4. "Peierls Mechanism of the Metal-Insulator Transition in Ferromagnetic Hollandite K₂Cr₈O₁₆", T. Toriyama, A. Nakao, Y. Yamaki, H. Nakao, Y. Murakami, K. Hasegawa, M. Isobe, Y. Ueda, A.V. Ushakov, D. I. Khomskii, S.V. Streltsov, T. Konishi, and Y. Ohta, Phys. Rev. Lett. 107 (2011) 266402-1-5.

List of publications: 2003-2012, 1994-2002

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This page updated on January 10, 2013