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thin filmYoneda, Yasuhiro; Tanida, Hajime*; Takagaki, Masafumi*; Uruga, Tomoya*
Transactions of the Materials Research Society of Japan, 35(1), p.99 - 102, 2010/03
Depth dependency of local structure of SrTiO thin film was investigated by X-ray absorption fine structure (XAFS). In epitaxial thin films, a large strain exists between substrates and grown films. The expitaxial strain is the largest in the interface and it is relaxed as parting from the substrate. The lattice parameter of the grown film changes depending on the lattice strain. We performed depth-resolved XAFS measurements on SrTiO thin film grown on LaAlO substrate. The depth-resolved XAFS can extract the local structures around the surface and inner regions separately. It was clarified that the bond distance between Sr and O changed greatly depending on the depth. On the other hand, the bond distance between Sr and Ti unchanged.
Iwase, Akihiro*; Fukuzumi, Masafumi*; Zushi, Yoshihiro*; Suzuki, Motohiro*; Takagaki, Masafumi*; Kawamura, Naomi*; Chimi, Yasuhiro; Mizuki, Junichiro; Ishikawa, Norito; Ono, Fumihisa*
Nuclear Instruments and Methods in Physics Research B, 256(1), p.429 - 433, 2007/01
Times Cited Count：17 Percentile：73.75(Instruments & Instrumentation)We have studied the effects of swift heavy ion irradiation on the magnetic properties of Fe-Rh intermetallic compound by using Fe K-edge X-ray magnetic circular dichroism (XMCD) at 20 K. For an unirrdaiated specimen, no signal of XMCD spectrum has been observed because Fe-Rh intermetallic compound is intrinsically anti-ferromagnetic below room temperature. For the specimens irradiated with 120-200 MeV Ni, Kr, Xe or Au ions, we have found XMCD spectra which are characterized by a dispersion-type profile with a positive peak and a negative peak near Fe K-edge. The intensity of XMCD spectra remarkably depends on ion-fluence and ion-mass. The experimental result implies that the ferromagnetic state is induced by the swift heavy ion irradiation. The change in magnetic state of Fe element is discussed in terms of energy deposition through the elastic and electronic processes.
Fukuzumi, Masafumi*; Chimi, Yasuhiro; Ishikawa, Norito; Suzuki, Motohiro*; Takagaki, Masafumi*; Mizuki, Junichiro; Ono, Fumihisa*; Neumann, R.*; Iwase, Akihiro*
Nuclear Instruments and Methods in Physics Research B, 245(1), p.161 - 165, 2006/04
Times Cited Count：17 Percentile：74.61(Instruments & Instrumentation)We have performed swift heavy ion irradiations in Fe-50at.%Rh alloys at room temperature. Before and after the irradiations, the magnetic properties and the lattice structure are measured using Superconducting QUantum Interference Device (SQUID) and X-Ray Diffractometer (XRD), respectively. We have also performed X-ray Magnetic Circular Dichroism (XMCD) measurement near the Fe K-edge at the synchrotron radiation facility, SPring-8, to examine the irradiation-induced ferromagnetic state near the specimen surface. We have found that the swift heavy ion irradiations induce the ferromagnetic state in Fe-50at.%Rh alloy below the antiferromagnetism-ferromagnetism transition temperature of the unirradiated alloy and the lattice expasion by 0.3%. For the specimens irradiated with swift heavy ions, we observe the XMCD spectra correponding to ferromagnetisim, which depend on the mass of irradiating ions and/or irradiation fluence. Effects of energy loss through electronic excitation and elastic collisions on lattice and magnetic structures of Fe-Rh alloy are discussed.
Ishikawa, Norito; Kawasuso, Atsuo; Takagaki, Masafumi*; Suzuki, Motohiro*; Mizuki, Junichiro; Zushi, Yoshihiro*; Fujita, Naoki*; Hori, Fuminobu*; Seki, Shuhei*; Tsukuda, Satoshi*; et al.
no journal, ,
It is already found that magnetic transition temperature of Fe-50at.%Rh changes by high-energy ion irradiation. This irradiation-induced changes in magnetic properties has been investigated by magnetic force microscopy. It has been found that microscopic magnetic structure appears after ion-irradiation, and the structure changes depending on the ion-fluence. The observed structure was not the same as that observed for Fe-rich ferromagnetic Fe-45at.%Rh alloys.
thin filmYoneda, Yasuhiro; Uruga, Tomoya*; Tanida, Hajime*; Takagaki, Masafumi*
no journal, ,
Depth dependency of local structure of SrTiO thin film was investigated by X-ray absorption fine structure (XAFS). In epitaxial thin films, a large strain exists between substrates and grown films. The epitaxial strain is the largest in the interface and it is relaxed as parting from the substrate. The lattice parameter of the grown film changes depending on the lattice strain. We performed depth-resolved XAFS measurements on SrTiO thin film grown on LaAlO substrate. The depth-resolved XAFS can extract the local structures around the surface and inner regions separately. It was clarified that the bond distance between Sr and O changed greatly depending on the depth. On the other hand, the bond distance between Sr and Ti unchanged.
