Reentrant Spin Glass Behavior in Cr-Doped Perovskite Manganite

Dho, Joonghoe; Kim, W. S.; Hur, Nam Hwi

doi:10.1103/physrevlett.89.027202

Cited by 269 publications

(171 citation statements)

References 32 publications

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“…The ferromagnetic clusters in such a case would not be associated with a well-defined global ferromagnetic transition temperature. This behavior is similar to that of microporous carbon and the members of the rare-earth manganite family with the formula RE 1−x A x MnO 3 (RE = rare-earth, A = alkalineearthelement) [47][48][49][50]. Recent theoretical calculations do indeed predict the presence of antiferromagnetic states in the sheets and ferromagnetic states at the edges of graphene [51].…”

Section: Magnetic Properties Of Few-layer Graphenesmentioning

confidence: 59%

A study of the synthetic methods and properties of graphenes

Rao

Subrahmanyam

Matte

et al. 2010

Science and Technology of Advanced Materials

181

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Graphenes with varying number of layers can be synthesized by using different strategies. Thus, single-layer graphene is prepared by micromechanical cleavage, reduction of single-layer graphene oxide, chemical vapor deposition and other methods. Few-layer graphenes are synthesized by conversion of nanodiamond, arc discharge of graphite and other methods. In this article, we briefly overview the various synthetic methods and the surface, magnetic and electrical properties of the produced graphenes. Few-layer graphenes exhibit ferromagnetic features along with antiferromagnetic properties, independent of the method of preparation. Aside from the data on electrical conductivity of graphenes and graphene-polymer composites, we also present the field-effect transistor characteristics of graphenes. Only single-layer reduced graphene oxide exhibits ambipolar properties. The interaction of electron donor and acceptor molecules with few-layer graphene samples is examined in detail.

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Section: Magnetic Properties Of Few-layer Graphenesmentioning

confidence: 59%

A study of the synthetic methods and properties of graphenes

Rao

Subrahmanyam

Matte

et al. 2010

Science and Technology of Advanced Materials

181

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“…In the present case, the spin glass is not of conventional type rather it has a reentrant character, where the sample first orders ferromagnetically from a paramagnetic state below T C = 340 K, and below a temperature T f near the step-like anomaly, the sample further transforms from the ordered FM to a disordered glassy magnetic phase. Reentrant spin glass (RSG) behavior has been observed in variety of magnetic systems including metallic alloys and oxides [19,20]. Our data on the EB measurement show that low temperature non-ferromagnetic ordering/freezing in the system responsible for the EB occurs at around the step-like anomaly, and field cooling from this temperature is sufficient enough to obtain the desired field shift in the isothermal magnetization measurements.…”

mentioning

confidence: 69%

Reentrant-spin-glass state inNi2Mn1.36Sn0.64shape-memory alloy

et al. 2009

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The ground state properties of the ferromagnetic shape memory alloy of nominal composition Ni2Mn1.36Sn0.64 have been studied by dc magnetization and ac susceptibility measurements. Like few other Ni-Mn based alloys, this sample exhibits exchange bias phenomenon. The observed exchange bias pinning was found to originate right from the temperature where a step-like anomaly is present in the zero-field-cooled magnetization data. The ac susceptibility study indicates the onset of spin glass freezing near this step-like anomaly with clear frequency shift. The sample can be identified as a reentrant spin glass with both ferromagnetic and glassy phases coexisting together at low temperature at least in the field-cooled state. The result provides us an comprehensive view to identify the magnetic character of various Ni-Mn-based shape memory alloys with competing magnetic interactions.PACS numbers: 75.50. Lk, 75.60.Nt,75.47.Np Recently Ni 2 Mn 1+x Z 1−x (Z = In, Sn, and Sb) based ferromagnetic shape memory alloys (FSMAs) have attracted considerable attention due to their multifunctional properties, which include magnetic sueprelasticity, giant magnetoresistance, large inverse magnetocaloric effect and magnetic memory effect [1,2,3,4,5]. The observed phenomena are primarily related to the magnetic field (H) induced reverse transition across the martensitic transformation (MT) [6]. The stoichiometric Heusler compositions (Ni 2 MnZ) are all ferromagnetic with the Curie point (T C ) lying just above room temperature. The excess Mn doping at the expense of Z atoms induces structural instability in the system leading to the ferromagnetic shape memory effect. Short range antiferromagnetic (AFM) interaction between the excess Mn (at the Z site) and the original Mn atoms has been predicted for the doped alloys [7,8]. Although, predominantly ferromagnetic (FM) character is present in the Mn doped alloys with T C around 300 K, the AFM correlation is evident from the gradual decrease of saturation moment with increasing amount of excess Mn [7,9]. Diffuse peaks observed in the powder neutron diffraction data of Ni-Mn-Sn alloys also indicate the existence of incipient AFM coupling [10].Evidently, the magnetic nature of the ground state of the alloys may not be very simple. A fascinating evidence for the complex ground state of the alloys is the recently observed exchange bias (EB) phenomenon in bulk samples [9,11,12]. EB is referred to the shift of the center of the magnetic hysteresis loop from the origin when the sample has been cooled from high temperature in presence of magnetic field [13]. The origin of EB is gener- * Electronic address: sspsm2@iacs.res.in ally ascribed to the presence of FM and AFM interfacial coupling in a heterogeneous sample. EB has also been observed in materials having FM/spin-glass (SG) and FM/Ferrimagnet interfaces [14,15] other than FM/AFM systems. However in all the cases, it is required that the ordering temperature (T N F ) for the non-ferromagnetic phase (may be AFM, SG or ferrimagnet) should be l...

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“…While the basic phenomena have been understood qualitatively, a full description by the theory was still lacking. Today the spin glass has become a fundamental and general form of magnetism and is still an active field of research [103,104,105,106,107,108,109,110].…”

Section: Spin Glassesmentioning

confidence: 99%