Giant magnetoresistance observed in metamagnetic bulk-MnAu2

Samata, H.; Sekiguchi, N.; Sawabe, Atsuhito; Nagata, Y.; Uchida, Takayuki; Lan, M. D.

doi:10.1016/s0022-3697(97)00198-4

Cited by 22 publications

(27 citation statements)

References 13 publications

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“…The tetragonal material MnAu 2 is one of the oldest known spin-spiral materials [1][2][3], with a Néel temperature of T N = 363 K [1] and a local Mn moment of 3.5µ B [3,4]. The magnetic ground state consists of inplane ferromagnetic Mn layers with a screw-type pattern around the tetragonal c axis, which can be described using the spiral angle θ [this is equivalent to the wave vector q = (0, 0, q z ), where θ = q z c/2].…”

Section: Introductionmentioning

confidence: 99%

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Collapse and control of theMnAu2spin-spiral state through pressure and doping

Glasbrenner

2016

Phys. Rev. B

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MnAu2 is a spin-spiral material with in-plane ferromagnetic Mn layers that form a screw-type pattern around a tetragonal c axis. The spiral angle θ was shown using neutron diffraction experiments to decrease with pressure, and in later studies it was found to suffer a collapse to a ferromagnetic state above a critical pressure, although the two separate experiments did not agree on whether this phase transition is first or second order. To resolve this contradiction, we use density functional theory calculations to investigate the spiral state as a function of pressure, charge doping, and also electronic correlations via a Hubbard-like U . We fit the results to the one-dimensional J1−J2−J3−J4 Heisenberg model, which predicts either a first-or second-order spiral-to-ferromagnetic phase transition for different regions of parameter space. At ambient pressure, MnAu2 sits close in parameter space to a dividing line separating first-and second-order transitions, and a combination of pressure and electron doping shifts the system from the first-order region into the second-order region. Our findings demonstrate that the contradiction in pressure experiments regarding the kind of phase transition are likely due to variations in sample quality. Our results also suggest that MnAu2 is amenable to engineering via chemical doping and to controlling θ using pressure and gate voltages, which holds potential for integration in spintronic devices.

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Section: Introductionmentioning

confidence: 99%

“…The spiral state is known to collapse to a metamagnetic fan-like configuration when placed in a ∼ 10 kOe magnetic field at room temperature [1,2], which led to a revival of interest in MnAu 2 when it was found that this gives rise to a giant magnetoresistive effect [4].…”

Section: Introductionmentioning

confidence: 99%

Collapse and control of theMnAu2spin-spiral state through pressure and doping

Glasbrenner

2016

Phys. Rev. B

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“…Preparation and characterization of polycrystalline Mn 1−x Cr x Au 2 samples were reported previously [3,4]. The samples have almost the same Cr compositions as the nominal ones and the distribution of all the elements is homogeneous in the specimen as determined by the electron-probe microanalysis [4].…”

Section: Experiments and Theorymentioning

confidence: 97%

“…These compounds, which crystallize in the body-centered tetragonal structure, exhibit many interesting physical properties [1][2][3][4]. The MnAu 2 shows a metamagnetic transition from a spiral to a ferromagnetic structure below the Neel temperature (T N ) of 365 K and above the threshold magnetic field (H th ) of about 10 kOe at 300 K [3]. The T N , H th , and the helical angle of the helical-spin configuration all decrease as the Cr content x increases [3].…”

Section: Introductionmentioning

confidence: 99%

“…The MnAu 2 shows a metamagnetic transition from a spiral to a ferromagnetic structure below the Neel temperature (T N ) of 365 K and above the threshold magnetic field (H th ) of about 10 kOe at 300 K [3]. The T N , H th , and the helical angle of the helical-spin configuration all decrease as the Cr content x increases [3]. The lattice constants a (=b) and c of MnAu 2 is 3.387 and 8.810Å, respectively, and decrease as the Cr contents increase [4].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and theoretical study of the electronic structures of Mn1−xCrxAu2

Hsu¹,

Wang

Tai

2006

Journal of Alloys and Compounds

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Festkörperchemie 1998

Janek

Ruck

1999

Nachr. Chem. Tech. Lab.

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Neben der Praparation und der strukturellen Charakterisierung neuer Verbindungen stehen zunehmend Untersuchungen zu den physikalischen Eigenschaften und zum mesoskopischen Aufbau der Substanzen im Mittelpunkt des Interesses. Dabei wird vermehrt auf die Kombination verschiedener, sich in lhren Aussagen erganzender Methoden ge-seM. Verstarkt hat sich der Trend zur Erforschung neuer Materialien und Werkstoffe, insbesondere fur den Einsatz im Bereich der Nanotechnologie. Erhohte Aufmerksamkeit findet auch das Studium der Kinetik von Festkorperreaktionen. lntermetallische Verbindungen und Zintl-PhasenEin umfangreiches System von Gruppe-Untergruppe-Beziehungen verbindet die neuen intermetallischen Phasen CaCuGe. GaAuIn, CaAuSn und MPdSi (M = Y, Gd -Lu) mit bekannten Strukturtypen und dem Aristotyp AIBz. Bemerkenswert ist die Moglichkeit der Strukturvorhersage verwandter, aber bislang unbekannter Verbindungen alleine aus der Kenntnis von Raumgruppe und Gitterparametern.') Die neuen ternaren Silicide La15Ni7Silo und LaZINillSils gehoren zu einer homologen Reihe hexagonaler Verbindungen der allgemeinen Formel La(n+i)(n+2)Nin(n-i)+zSin~n+i), in der sie die Glieder mit n = 4 bzw. n = 5 darstellen. Charakteristisch fur den Aufbau sind Baueinheiten in Form gleichseitiger Dreiecke mit der Kantenlange n, die als Ausschnitte aus dem AIB2-Typ angesehen werden konnen.') Magnetische und elektrische Messungen an der tetragonalen Phase MnAu2 belegen einen GMR-Effekt (GMR= giant magnetoresistance, iibergroBer Magnetwiderstand) in der GroRe von 10 % bei Raumtemperatur und ei-I Kalorimeter, Druckbehalter, Reaktoren, AufschluOsysterne DruckTemp: bis max. 350 bar I350" C Material: Edelstahl und ijber 10 weitere Werkstoffe Neue cornputergestutzte Steuerungs-und uberwachungssysterne fur Reaktor-und Mini-Plant-Anlagen Parr instrument (Deutschland) GmbH RoRkopfstraBe 25 D -60439 Frankfurt a. M.

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Giant magnetoresistance observed in metamagnetic bulk-MnAu2

Cited by 22 publications

References 13 publications

Collapse and control of theMnAu2spin-spiral state through pressure and doping

Collapse and control of theMnAu2spin-spiral state through pressure and doping

Experimental and theoretical study of the electronic structures of Mn1−xCrxAu2

Festkörperchemie 1998

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