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We have studied low frequency resistance fluctuations (noise) in a single crystal of the rare earth perovskite manganite Pr$_{0.63}$Ca$_{0.37}$MnO$_3$ which shows a charge ordering transition at a temperature $T_{CO}$ ~ 245K. The noise…

Strongly Correlated Electrons · Physics 2007-05-23 Aveek bid , Ayan Guha , A. K. Raychaudhuri

We present the first study relating structural parameters of precipitate free Ge0.95Mn0.05 films to magnetisation data. Nanometer sized clusters - areas with increased Mn content on substitutional lattice sites compared to the host matrix -…

Materials Science · Physics 2009-11-11 D. Bougeard , S. Ahlers , A. Trampert , N. Sircar , G. Abstreiter

We have performed a systematic analysis of the low frequency 1/f-noise in single grain boundary junctions in the colossal magnetoresistance material La_{2/3}Ca_{1/3}MnO_{3-delta}. The grain boundary junctions were formed in epitaxial…

Strongly Correlated Electrons · Physics 2009-11-07 J. B. Philipp , L. Alff , A. Marx , R. Gross

We report the observation of nuclear magnetic resonance (NMR) in a ferromagnet-semiconductor heterostructure in the presence of a spin-polarized current. Spin-polarized electrons injected from a metallic ferromagnet generate a large nuclear…

Condensed Matter · Physics 2009-11-10 J. Strand , B. D. Schultz , A. F. Isakovic , X. Lou , C. J. Palmstrom , P. A. Crowell

We have investigated the magnetic properties of (Ga,Mn)As thin films with Mn concentration between 1 and 9%. Ferromagnetic transition temperatures TC of up to 173K are observed. The results are compared to the predictions of the Zener…

Strongly Correlated Electrons · Physics 2009-11-10 K. Y. Wang , R. P. Campion , K. W. Edmonds , M. Sawicki , T. Dietl , C. T. Foxon , B. L. Gallagher

Ion implantation of Mn combined with pulsed laser melting is employed to obtain two representative compounds of dilute ferromagnetic semiconductors (DFSs): Ga1-xMnxAs and In1-xMnxAs. In contrast to films deposited by the widely used…

Taking advantage of the anomalous Hall effect, we electrically probe low-frequency magnetization fluctuations at room temperature in a thin ferromagnetic Pt/Co/AlO$_x$ layer stack with perpendicular magnetic anisotropy. We observe a strong…

Mesoscale and Nanoscale Physics · Physics 2024-02-29 Nadine Nabben , Giacomo Sala , Ulrich Nowak , Matthias Krüger , Sebastian T. B. Goennenwein

When probing nuclear spins in materials on the nanometer scale, random fluctuations of the spin polarization will exceed the mean Boltzmann polarization for sample volumes below about (100nm)^3. In this work, we use magnetic resonance force…

Mesoscale and Nanoscale Physics · Physics 2008-01-14 C. L. Degen , M. Poggio , H. J. Mamin , D. Rugar

A narrow-gap ferromagnetic In(1-x)Mn(x)Sb semiconductor alloy was successfully grown by low-temperature molecular beam epitaxy on CdTe/GaAs hybrid substrates. Ferromagnetic order in In(1-x)Mn(x)Sb was unambiguously established by the…

A single-domain nanomagnet, shaped like a thin elliptical disk with small eccentricity, has a double well potential profile with two degenerate energy minima separated by a small barrier of a few kT (k = Boltzmann constant and T = absolute…

Mesoscale and Nanoscale Physics · Physics 2024-07-24 Rahnuma Rahman , Supriyo Bandyopadhyay

The discovery of ferromagnetism in Mn doped GaAs [1] has ignited interest in the development of semiconductor technologies based on electron spin and has led to several proof-of-concept spintronic devices [2-4]. A major hurdle for realistic…

Materials Science · Physics 2009-11-11 Dale Kitchen , Anthony Richardella , Jian-Ming Tang , Michael E. Flatte , Ali Yazdani

In this paper, we demonstrate external control over the magnetization direction in ferromagnetic (FM) In_{1-x}Mn_{x}As/GaSb heterostructures. FM ordering with T_C as high as 50 K is confirmed by SQUID magnetization, anomalous Hall effect…

The origin of ferromagnetism in semimagnetic III-V materials is discussed. The indirect exchange interaction caused by virtual electron excitations from magnetic impurity level in the bandgap to the valence band can explain ferromagnetism…

Materials Science · Physics 2009-11-07 V. I. Litvinov , V. K. Dugaev

The natural world is replete with examples of multistable systems, known to respond to periodic modulations and produce a signal, which exhibits resonance with noise amplitude. This is a concept not demonstrated in pure materials, which…

Mesoscale and Nanoscale Physics · Physics 2014-07-15 Satyendra Prakash Pal , P Sen

We have studied the atomic and magnetic structure of the dilute ferromagnetic semiconductor system (Ba,K)(Zn,Mn)$_2$As$_2$ through atomic and magnetic pair distribution function analysis of temperature-dependent x-ray and neutron total…

The magnetization and hole distribution of Mn clusters in (Ga,Mn)As are investigated by all-electron total energy calculations using the projector augmented wave method within the density-functional formalism. It is found that the…

Materials Science · Physics 2009-11-11 H. Raebiger , A. Ayuela , J. von Boehm

We report on unusual magnetic properties observed in the nanofluid room-temperature ferromagnetic graphite (with an average particle size of l=10nm). More precisely, the measured magnetization exhibits a low-temperature anomaly (attributed…

Most conventional magnetic materials used in the electronic devices are ferrites, which are composed of micrometer-size grains. But ferrites have small saturation magnetization, therefore the performance at GHz frequencies is rather poor.…

Materials Science · Physics 2015-03-19 J. V. I. Timonen , R. H. A. Ras , O. Ikkala , M. Oksanen , E. Seppala , K. Chalapat , J. Li , G. S. Paraoanu

A new scenario of the mechanism of intriguing ferromagnetic properties in Mn-doped magnetic semiconductor (Ga,Mn)As is examined in detail. We find that magnetic features seen in zero-field cooled and field cooled magnetizations are not…

Materials Science · Physics 2009-11-11 K. Hamaya , T. Koike , T. Taniyama , T. Fujii , Y. Kitamoto , Y. Yamazaki

High 1/f noise in CryoCMOS devices is a critical parameter to keep under control in the design of complex circuits for low temperatures applications. Current models predict the 1/f noise to scale linearly with temperature, and gate oxide…