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Title: Interface Fe magnetic moment enhancement in MgO/Fe/MgO trilayers

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3];  [3];  [4]; ORCiD logo [5];  [5];  [6];  [7];  [7];  [6]; ORCiD logo [3]
  1. CNRS, Inst NEEL, F-38042 Grenoble, France, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
  2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
  3. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
  4. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA, Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
  5. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
  6. IBM Almaden Research Center, San Jose, California 95120, USA, Max-Planck Institute for Microstructure Physics, 06120 Halle (Saale), Germany
  7. IBM Almaden Research Center, San Jose, California 95120, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1229657
Grant/Contract Number:
AC02- 05CH11231; AC02-76SF00515
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 107; Journal Issue: 9; Related Information: CHORUS Timestamp: 2018-03-29 14:28:40; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Jal, Emmanuelle, Kortright, Jeffrey B., Chase, Tyler, Liu, TianMin, Gray, Alexander X., Shafer, Padraic, Arenholz, Elke, Xu, Pengfa, Jeong, Jaewoo, Samant, Mahesh G., Parkin, Stuart S. P., and Dürr, Hermann A. Interface Fe magnetic moment enhancement in MgO/Fe/MgO trilayers. United States: N. p., 2015. Web. doi:10.1063/1.4929990.
Jal, Emmanuelle, Kortright, Jeffrey B., Chase, Tyler, Liu, TianMin, Gray, Alexander X., Shafer, Padraic, Arenholz, Elke, Xu, Pengfa, Jeong, Jaewoo, Samant, Mahesh G., Parkin, Stuart S. P., & Dürr, Hermann A. Interface Fe magnetic moment enhancement in MgO/Fe/MgO trilayers. United States. doi:10.1063/1.4929990.
Jal, Emmanuelle, Kortright, Jeffrey B., Chase, Tyler, Liu, TianMin, Gray, Alexander X., Shafer, Padraic, Arenholz, Elke, Xu, Pengfa, Jeong, Jaewoo, Samant, Mahesh G., Parkin, Stuart S. P., and Dürr, Hermann A. Tue . "Interface Fe magnetic moment enhancement in MgO/Fe/MgO trilayers". United States. doi:10.1063/1.4929990.
@article{osti_1229657,
title = {Interface Fe magnetic moment enhancement in MgO/Fe/MgO trilayers},
author = {Jal, Emmanuelle and Kortright, Jeffrey B. and Chase, Tyler and Liu, TianMin and Gray, Alexander X. and Shafer, Padraic and Arenholz, Elke and Xu, Pengfa and Jeong, Jaewoo and Samant, Mahesh G. and Parkin, Stuart S. P. and Dürr, Hermann A.},
abstractNote = {},
doi = {10.1063/1.4929990},
journal = {Applied Physics Letters},
number = 9,
volume = 107,
place = {United States},
year = {Tue Sep 01 00:00:00 EDT 2015},
month = {Tue Sep 01 00:00:00 EDT 2015}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4929990

Citation Metrics:
Cited by: 4works
Citation information provided by
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  • We grow monocrystalline Fe(001) films and Fe/Si/Fe(001) trilayers by ion-beam sputter epitaxy on GaAs(001) and MgO(001) substrates. Ion-beam sputtering parameters such as substrate presputtering time, substrate temperature, beam voltage, and target angle are optimized for 10-nm-thick Fe(001) films with respect to epitaxial growth and magnetic properties. In situ low-energy electron diffraction patterns confirm the epitaxial and monocrystalline nature of the sputtered films, surprisingly even on untreated and thus oxidized substrates. The magneto-optical Kerr effect and ferromagnetic resonance are employed to investigate the magnetic properties, and the structural properties are characterized by atomic force microscopy and x-ray reflectivity measurements. Using themore » optimized set of parameters that yields the best magnetic properties for single Fe films on GaAs, we deposit epitaxial Fe/Si/Fe(001) structures and observe antiferromagnetic interlayer exchange coupling for epitaxially sputtered Fe/Si/Fe(001) trilayers on GaAs(001). The total coupling strength reaches values of up to 2 mJ/m{sup 2} at a Si thickness of 15 A.« less
  • A series of Fe/MgO/Fe(100) trilayer structures with MgO thicknesses ranging from 12 to 1000 {Angstrom} was grown at 75 {degree}C by molecular beam epitaxy. The structures are all epitaxial, and for MgO thicknesses below 75 {Angstrom}, the Fe layers are ferromagnetically coupled. The MgO spacer thickness dependence of the coupling energy shows a change in slope at 25 {Angstrom}, suggesting a change in growth morphology. Perpendicular transport measurements show ohmic current-voltage characteristics with high conductance up to 1000 {Angstrom} MgO interlayer thicknesses, indicating that the coupling is not due to spin-dependent tunneling. Investigations of the growth morphology reveal the existencemore » of ferromagnetic bridges across the MgO layer. {copyright} {ital 1997 American Institute of Physics.}« less
  • The knowledge of chemical and magnetic conditions at the Co{sub 40}Fe{sub 40}B{sub 20}/MgO interface is important to interpret the strong annealing temperature dependence of tunnel magnetoresistance of Co-Fe-B/MgO/Co-Fe-B magnetic tunnel junctions, which increases with annealing temperature from 20% after annealing at 200 C up to a maximum value of 112% after annealing at 350 C. While the well defined nearest neighbor ordering indicating crystallinity of the MgO barrier does not change by the annealing, a small amount of interfacial Fe-O at the lower Co-Fe-B/MgO interface is found in the as grown samples, which is completely reduced after annealing at 275more » C. This is accompanied by a simultaneous increase of the Fe magnetic moment and the tunnel magnetoresistance. However, the TMR of the MgO based junctions increases further for higher annealing temperature which can not be caused by Fe-O reduction. The occurrence of an x-ray absorption near-edge structure above the Fe and Co L-edges after annealing at 350 C indicates the recrystallization of the Co-Fe-B electrode. This is prerequisite for coherent tunneling and has been suggested to be responsible for the further increase of the TMR above 275 C. Simultaneously, the B concentration in the Co-Fe-B decreases with increasing annealing temperature, at least some of the B diffuses towards or into the MgO barrier and forms a B{sub 2}O{sub 3} oxide.« less
  • Low-voltage spin-dependent tunneling spectroscopy of an epitaxial Fe/MgO/Fe magnetic tunnel junction is measured and compared to first-principles calculation of the tunneling conductance. The measured dynamic conductance ($dI/dV$) in the parallel configuration shows distinct asymmetric features as a function of the bias voltage $V$. The peaks are independent of barrier thickness, magnetic field, and temperature. From the first-principles calculation, we identify the positive and negative bias spectra corresponding to different types of Fe/MgO interfaces. Tunneling spectroscopy thus can be used as a powerful tool for interface characterization.
  • Following predictions by first-principles theory of huge tunnel magnetoresistance (TMR) effect in epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs), measured magnetoresistance (MR) ratio about 200% at room temperature (RT) have been reported in MgO-based epitaxial MTJs. Recently, MR ratio of about 600% has been reported at RT in MgO-based amorphous MTJs with core structure of CoFeB/MgO/CoFeB grown by magnetron sputtering with amorphous CoFeB layers. The sputtered CoFeB/MgO/CoFeB MTJs shows a great potential application in spintronic devices. Although epitaxial structure will probably not be used in devices, it remains an excellent model system to compare theoretical calculations with experimental results and tomore » enhance our understanding of the spin dependent tunneling. Both theoretical calculations and experimental results clearly indicate that the interfacial structure plays a crucial role on coherent tunneling across single crystalMgO barrier, especially in epitaxial MgO-based MTJs grown by molecular beam epitaxy (MBE). Surface X-ray diffraction, Auger electron spectroscopy, X-ray absorption spectra, and X-ray magnetic circular dichroism have been used for interface characterization. However, no consistent viewpoint has been reached, and this is still an open issue. In this article, recent studies on the interface characterization in MgO-based epitaxial MTJs will be introduced, with a focus on research by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and spin dependent tunneling spectroscopy.« less