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Title: Anomalous oscillatory magnetoresistance in superconductors

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1282428
Grant/Contract Number:
FG02-99ER45763
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 5; Related Information: CHORUS Timestamp: 2016-08-04 18:09:25; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Kunchur, Milind N., Dean, Charles L., and Ivlev, Boris I. Anomalous oscillatory magnetoresistance in superconductors. United States: N. p., 2016. Web. doi:10.1103/PhysRevB.94.054504.
Kunchur, Milind N., Dean, Charles L., & Ivlev, Boris I. Anomalous oscillatory magnetoresistance in superconductors. United States. doi:10.1103/PhysRevB.94.054504.
Kunchur, Milind N., Dean, Charles L., and Ivlev, Boris I. 2016. "Anomalous oscillatory magnetoresistance in superconductors". United States. doi:10.1103/PhysRevB.94.054504.
@article{osti_1282428,
title = {Anomalous oscillatory magnetoresistance in superconductors},
author = {Kunchur, Milind N. and Dean, Charles L. and Ivlev, Boris I.},
abstractNote = {},
doi = {10.1103/PhysRevB.94.054504},
journal = {Physical Review B},
number = 5,
volume = 94,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.94.054504

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  • A superconducting La{sub 1.84}Sr{sub 0.16}CuO{sub 4} film patterned into a network of 100 x 100 nm{sup 2} noninteracting square loops exhibits large magnetoresistance oscillations superimposed on a background which increases monotonically with the applied magnetic field. Neither the oscillations amplitude nor its temperature dependence can be explained by the Little-Parks effect. Conversely, a good quantitative agreement is obtained with a recently proposed model ascribing the oscillations to the interaction between thermally excited moving vortices and the oscillating persistent currents induced in the loops. Extension of this model, allowing for direct interaction of the vortices and antivortices magnetic moment with themore » applied field, accounts quantitatively for the monotonic background as well. Analysis of the background indicates that in the patterned film both vortices and antivortices are present at comparable densities. This finding is consistent with the occurrence of Berezinskii-Kosterlitz-Thouless transition in La{sub 1.84}Sr{sub 0.16}CuO{sub 4} films.« less
  • The effect of Cr(001) insertion layers in Fe(001)/MgO/Cr/Fe magnetic tunneling junctions (MTJs) is studied from first-principles. It is shown that with the increase of the Cr(001) layer thickness, the tunneling magnetoresistance (TMR) first decreases rapidly and then oscillates with a two-monolayer period. At some thicknesses, the oscillation leads to a sign reversal of the TMR. The oscillatory interfacial Cr moment at the Cr-MgO interface as a function of the Cr layer thickness, which arises from the layer-anti-ferromagnetic ordering of Cr, is the cause for the oscillatory TMR.
  • Size-dependent oscillations in the magnetoresistance and Hall effect in cadmium have been studied using the field-modulation method. Nine sets of oscillations were observed for the first time and three sets disoovered previously were observed with greater resolution over a larger range of field orientations. Most of the oscillations are assigned to orbits on the second-band monster'' and third-band lens'' sheets of the Fermi surface. The results indicate a slight departure of the lens from axial symmetry. Considerable second- harmonic content was observed on some of thc oscillations. Disappearance of somer monster oscillations but not the lens oscillations in magnetic fieldsmore » greater than 8 kOe is attributed to the effect of magnetic breakdown of the energy gap between the first and second bands. Results are discussed in terms of the size-effect theory of Bloomfield and the Fermi-surface model of Stark and Falicov. (auth)« less
  • A epitaxial orientation of Fe/Cr superlattices---Fe/Cr(211) on MgO(110)---is grown by magnetron sputtering. Its structural and magnetic characterizations are presented and compared to those for Fe/Cr(100) superlattices grown simultaneously onto MgO(100) substrates. The epitaxial orientation of the Fe/Cr(211) superlattices is Fe/Cr[0[bar 1]1][parallel]MgO[001] and Fe/Cr[[bar 1]11][parallel]MgO[1[bar 1]0], while that for Fe/Cr(100) is Fe/Cr[001][parallel] MgO[011]. A uniaxial, in-plane surface anisotropy for the Fe/Cr(211) superlattices along the Fe[0[bar 1]1] of 0.06 erg/cm[sup 2] is obtained from analysis of the magnetization hysteresis loops. Four oscillations in the antiferromagnetic interlayer coupling and giant magnetoresistance (GMR) are observed with a period of 18 A for both orientations.more » The strength, oscillation period, and phase of the magnetic coupling are identical for the two orientations. The GMR values increase by a factor of [similar to]4 to 5 on cooling from room temperature to 4.2 K. At 4.2 K the maximum GMR value of the [Fe(14 A)/Cr(8 A)][sub 50] superlattice is 70% for the (211) orientation and 150% for the (100) orientation.« less