Papers by Keyword: Magnetoresistivity MR

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Authors: Alexander A. Lebedev, Pavel L. Abramov, Nina V. Agrinskaya, Ven I. Kozub, Alexey N. Kuznetsov, Sergey P. Lebedev, Gagik A. Oganesyan, A.V. Chernyaev, Dmitrii Shamshur, Maria O. Skvortsova
Abstract: n-type 3C-SiC films have been grown by sublimation epitaxy on hexagonal silicon carbide substrates. The low-temperature conductivity and magnetoresistance of the films have been studied in relation to their doping level and structural perfection. It was found that a metal--insulator transition occurs in the n-3C-SiC layer at concentrations Nd - Na ≤ 3 1017 cm-3.
Authors: V. Peña, N.M. Nemes, J. Garcia-Barriocanal, Z. Sefrioui, C. Leon, S.G.E. Te Velthuis, A. Hoffmann, M. Garcia-Hernandez, J.L. Martinez, J. Santamaría
Abstract: We report magnetoresistance in ferromagnet / superconductor / ferromagnet structures made of La0.7Ca0.3MnO3 and YBa2Cu3O7 in the current in plane (CIP) geometry when the temperature is fixed along the superconducting transition and the magnetic field is swept in an hysteresis loop sequence. We describe experiments changing the geometry of current versus field. We find that the shape and height of the magnetoresistance peaks is not modified no matter the field is directed parallel or perpendicular to the current. This excludes interpretations in terms of spontaneous vortices or anisotropic magnetoresistance of the ferromagnetic layers and supports the view that the magnetoresistance phenomenon originates at the spin dependent transport of quasiparticles transmitted from the ferromagnetic electrodes into the superconductor.
Authors: K.R. Krylov, N.K. Lerinman, A.I. Ponomarev, L.D. Sabirzjanova, N.G. Shelushinina, N.P. Gavaleshko, P.D. Marjanchuk
Authors: Subham Chatterjee, S. Majumdar
Abstract: The magnetic phase diagram of Ni2Mn1+xSn1−x based ferromagnetic (FM) shape memory alloys for varied concentrations of x have been studied. With increasing concentration of Mn, the FM Curie temperature (TC) decreases, while the martensitic transition temperature (TM) goes higher. For x = 0.44 and 0.48, TM is close to the onset of ferromagnetism, and two distinct magnetic transitions are observed corresponding to the TC’s of the FM phases of martensite and austenite respectively. The isothermal magnetization at 5 K indicates saturating behaviour at high fields and the saturation moment drops linearly with x. The samples show reasonably large negative magnetoresistance around TM, however the magnitude drops with increasing x. The magnetoresistance is found to be highly irreversible with respect to the applied magnetic field and field induced arrested state is observed for all the FM samples studied around the first order martensitic transition. The present investigation clearly indicates complex magnetic ground state of the Ni2Mn1+xSn1−x samples with competing magnetic interactions.
Authors: A. Harrou, Santiago Suriñach, Juan Santiago Muñoz Domínguez
Authors: Govindarajan Veeraraghavan, Tho Duc Nguyen, Yu Gang Sheng, Omer Mermer, Markus Wohlgenannt
Abstract: We report on the experimental observation of large magnetoresistance in Alq3 organic light-emitting diodes (OLEDs). Very similar magnetic field effects (MFEs) of comparable magnitude are also observed in electroluminescence and photocurrent measurements. We also report on the frequency response of the magnetoresistance effect at frequencies below 100 kHz. To the best of our knowledge, the mechanism causing these MFE is currently not known.
Authors: A.V. Bogach, S.V. Demishev, K. Flachbart, S. Gabani, V.V. Glushkov, A.V. Levchenko, N.Y. Shitsevalova, D.N. Sluchanko, N.E. Sluchanko
Abstract: High precision measurements of magnetoresistance =f(T,H) and magnetization M(T,H) have been carried out on single crystals of rare earth dodecaboride TmB12 at temperatures 1.8–30 K in magnetic fields up to 80 kOe. The high accuracy measurements and precise temperature stabilization allowed us to perform numerical differentiation and analyze quantitatively a behavior of derivative d()/dH=f(T,H) and magnetic susceptibility (T,H)=dM/dH in paramagnetic and magnetically ordered phases of thulium dodecaboride. It was shown that negative magnetoresistance anomalies observed in present study in paramagnetic state of TmB12 can be consistently interpreted in frameworks of a simple relation between resistivity and magnetization - /M2 proposed by K. Yosida (Phys. Rev., 107, 396 (1957)). A local magnetic susceptibility loc(T,H)=(1/H(d(/)/dH))1/2 was deduced directly from the magnetoresistance measurements and compared with bulk susceptibility (T,H)=dM/dH results of the present study. Moreover, the susceptibility dependences loc(T,H) and (T,H) have been applied to analyze in detail the H-T magnetic phase diagram of TmB12.
Authors: Sam Jin Kim, Seung Iel Park, Sung Baek Kim, Bo Wha Lee, Chul Sung Kim
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