Growth of epitaxial bcc Co(001) electrodes for magnetoresistive devices

Wieldraaijer, H Harm; LeClair, P.; Ha, K. F.; Jonge, de Wjm Wim

doi:10.1103/physrevb.67.224430

Cited by 30 publications

(24 citation statements)

References 46 publications

(95 reference statements)

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“…The growth of tetragonally distorted ð1 0 0Þ-oriented Co films has been reported for Co on Ptð1 0 0Þ [9], GaAsð1 0 0Þ [10], Geð1 0 0Þ [11], Feð1 0 0Þ [2,[12][13][14], FeAlð1 0 0Þ [15], Pdð1 0 0Þ [16,17], Wð1 0 0Þ [18,19] and Auð1 0 0Þ [20]. On Crð1 0 0Þ, Co grows pseudomorphically in a bcc structure for the first few monolayers followed by continuous relaxation towards hcp structure [21,22].…”

Section: Introductionmentioning

confidence: 92%

Reconstructed bcc Co films on the surface

Methfessel

Elmers

2007

Surface Science

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Section: Introductionmentioning

confidence: 92%

Reconstructed bcc Co films on the surface

Methfessel

Elmers

2007

Surface Science

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“…Therefore, in the calculation of Oleinik et al the strained Co layer proceeded along the Bain path from the fcc to the slightly distorted bcc structure. It is therefore likely that the top Co electrode in the experiments of de Teresa et al [19] grew in the bcc phase on SrTiO 3 , and that fully crystalline bcc Co/SrTiO 3 /Co(001) MTJs may be grown on a suitable substrate (see, e.g., experimental papers [44,45] on growth of bcc Co and a recent paper [46] showing a large TMR in bcc Co/MgO/Fe(001) MTJs). The spin-resolved conductance of a Co/SrTiO 3 /Co MTJ is shown in Fig.10b as a function of barrier thickness.…”

Section: Negative Spin Polarization In Co/srtio 3 /Co Tunnel Junctionsmentioning

confidence: 99%

Interface effects in spin-dependent tunneling

Tsymbal

Belashchenko

Velev

et al. 2007

Progress in Materials Science

100

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In the past few years the phenomenon of spin dependent tunneling (SDT) in magnetic tunnel junctions (MTJs) has aroused enormous interest and has developed into a vigorous field of research. The large tunneling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible application in random access memories and magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. One such question is the role of interfaces in MTJs and their effect on the spin polarization of the tunneling current and TMR. In this paper we consider different models which suggest that the spin polarization is primarily determined by the electronic and atomic structure of the ferromagnet/insulator interfaces rather than by their bulk properties. First, we consider a simple tight-binding model which demonstrates that the existence of interface states and their contribution to the tunneling current depend on the degree of hybridization between the orbitals on metal and insulator atoms. The decisive role of the interfaces is further supported by studies of spin-dependent tunneling within realistic first-principles models of Co/vacuum/Al, Co/Al 2 O 3 /Co, Fe/MgO/Fe, and Co/SrTiO 3 /Co MTJs. We find that variations in the atomic potentials and bonding strength near the interfaces have a profound effect resulting in the formation of interface resonant states, which dramatically affect the spin polarization and TMR. The strong sensitivity of the tunneling spin polarization and TMR to the interface atomic and electronic structure dramatically expands the possibilities for engineering optimal MTJ properties for device applications.

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“…Cobalt assumes hcp structure in bulk and fcc structure in thin films. It can also be grown in bcc structure on a Cr substrate [14] and on GaAs or Ge substrates covered with an Fe seed layer [15]. The equilibrium lattice parameter of bcc Co is 2.83 Å [16] which has only a 2.3% mismatch with the SrTiO 3 lattice rotated through 45…”

mentioning

confidence: 99%