Unusual Behavior in The Magnetic Anisotropy of Ultra-Thin Co Sandwiches: The Role of Au Underlayers.

1995 ◽  
Vol 384 ◽  
Author(s):  
Christian Marlière ◽  
Brad N. Engel ◽  
Charles M. Falco
Keyword(s):  
Magnetic Anisotropy ◽  
Coercive Field ◽  
Kerr Effect ◽  
Atomic Layer ◽  
Perpendicular Anisotropy ◽  
Unusual Behavior ◽  
Sharp Minimum ◽  
Polar Kerr Effect

ABSTRACTWe have used in situ polar Kerr effect measurements to study the magnetic anisotropy of X/Co/Y sandwich structures grown by MBE on Cu(111) buffers, where X and Y are variable thicknesses of Au. For fixed values of Y and in the case of an underlayer wedge, e.g. variable X value, we have found a sharp minimum in both coercive field and perpendicular anisotropy at ≈1 atomic layer of the Au underlayer. This anisotropy behavior is opposite to that of an Au overlayer deposited on a Co film, i.e. variable Y and fixed X.

Anomalous Perpendicular Anisotropy in Ultra-Thin Co Films

1993 ◽  
Vol 313 ◽  
Author(s):  
Michael H. Wiedmann ◽  
Brad N. Engel ◽  
Robert A. Van Leeuwen ◽  
Ko Mibu ◽  
Teruya Shinjo ◽  
...  
Keyword(s):  
Transition Metal ◽  
Kerr Effect ◽  
Atomic Layer ◽  
Perpendicular Anisotropy ◽  
Magnetic Metal ◽  
Layer 2 ◽  
Polar Kerr Effect ◽  
Total Coverage ◽  
Peak Value

ABSTRACTWe have used in situ polar Kerr effect measurements to study the magnetic coercivity and anisotropy of MBE-grown Pd (111) /Co/X and Au (111) /Co/X trilayers, where χ is the nonmagnetic noble or transition metal overlayer Ag, Cu or Pd. Polar hysteresis curves were Measured in situ for systematically varied Co and overlayer thicknesses 2 Å ≤ tco ≤ 20 Å and 0 Å ≤ tx ≤ 50 Å. We find the coercivity and total anisotropy display a strongly peaked perpendicular contribution at ∼1 atomic layer (2 Å) non-Magnetic Metal coverage. For Cu, where the effect is strongest, the total anisotropy energy rapidly decreases by a factor of 3 from its peak value after a total coverage of ∼2 atomic layers (4 A) of Cu.

Tuning the Magnetic Anisotropy of Fe3O4/Pt Heterostructures Fabricated by Atomic Layer Deposition With $In~Situ$ Magnetic Field

2019 ◽  
Vol 55 (3) ◽  
pp. 1-7 ◽  
Author(s):  
Le Zhang ◽  
Ziyao Zhou ◽  
Yijun Zhang ◽  
Bin Peng ◽  
Wei Ren ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Atomic Layer Deposition ◽  
Magnetic Anisotropy ◽  
Atomic Layer ◽  
Layer Deposition

Examining the role of hydrogen in the electrical performance of in situ fabricated metal-insulator-metal trilayers using an atomic layer deposited Al2O3 dielectric

2013 ◽  
Vol 102 (17) ◽  
pp. 173501 ◽  
Author(s):  
Alexander C. Kozen ◽  
Marshall A. Schroeder ◽  
Kevin D. Osborn ◽  
C. J. Lobb ◽  
Gary W. Rubloff
Keyword(s):  
Atomic Layer ◽  
Electrical Performance ◽  
Metal Insulator ◽  
Fabricated Metal ◽  
Metal Insulator Metal

Misfit Strain Relief Beyond the Critical Thickness Using Curvature Measurements and in Situ Characterization of the Magneto-Optic Kerr Effect

1994 ◽  
Vol 356 ◽  
Author(s):  
H. E. Inglefield ◽  
G. Bochi ◽  
C. A. Ballentine ◽  
R. C. O’Handley ◽  
C. V. Thompson
Keyword(s):  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Kerr Effect ◽  
Critical Thickness ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Wafer Curvature ◽  
Curvature Measurements ◽  
Magneto Optic

AbstractEpitaxial misfit has been characterized in Ni/Cu/Si (100) as a function of Ni film thickness using wafer curvature measurements. This strain can be related to measurements of magnetic anisotropy made in the deposition system using the magneto-optic Kerr effect. Films were deposited using molecular beam epitaxy (MBE) with varying Ni epilayer thickness between 10 and 1000Å. The change in wafer curvature due to misfit strain was measured using optical interferometry and the strain was calculated using Stoney’s equation. Transmission electron microscopy was used to characterize misfit dislocations at the Ni/Cu interface. It has been determined that misfit strain can have a very strong effect on magnetic anisotropy, particularly in the regime between the critical thickness and complete misfit accommodation, where strain has been found to decrease significantly as a function of film thickness. A critical strain has been determined at which a transition in the direction of magnetization easy axis from perpendicular to the film to in the film plane occurs. This discovery allows the use of Kerr effect measurements to characterize misfit strain in situ.

scholarly journals Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

2017 ◽  
Vol 8 ◽  
pp. 2389-2395 ◽  
Author(s):  
Sumit Tewari ◽  
Koen M Bastiaans ◽  
Milan P Allan ◽  
Jan M van Ruitenbeek
Keyword(s):  
Atomic Structure ◽  
Scanning Tunneling Microscope ◽  
Critical Role ◽  
Atomic Layer ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Stm Tips

Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

scholarly journals Fundamental Role Of The H2A.Z C-Terminal Tail In The Formation Of Constitutive Heterochromatin

2021 ◽  
Author(s):  
László Imre ◽  
Péter Nánási ◽  
Rosevalentine Bosire ◽  
Ágota Csóti ◽  
Kata Nóra Enyedi ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Constitutive Heterochromatin ◽  
Large Fraction ◽  
Gene Expression Pattern ◽  
Histone Variant ◽  
Unusual Behavior ◽  
Isoform Specificity ◽  
The Stability

ABSTRACTNucleosome stability, a crucial determinant of gene regulation, was measured in a robust in situ assay to assess the molecular determinants of the stability of H2A.Z-containig nucleosomes. Surprisingly, a large fraction of H2A.Z detected by three different antibodies was released from the nucleosomes by salt together with H3, and was associated with H3K9me3 but not with H3K27me3 marked nucleosomes. This unusual behavior relied on the presence of the unstructured C-terminal chain of the histone variant, rather than on isoform specificity, posttranslational modifications or binding of the reader protein PWWPA2, as determined using cell lines expressing only particular forms of the variant. In the absence of this tail, or upon addition of an excess of the tail peptide to the nuclei of control cells, the canonical H2A-like stability features were readily restored and most of the H2A.Z-containing nucleosomes left the periphery and ended up in scattered foci in the nuclei. Concomitantly, the H3K9me3-marked constitutive heterochromatin was also dispersed, what was accompanied by increased overall nuclease sensitivity and significantly enhanced binding of intercalating dyes to the DNA. The DT40 cells expressing the tailless H2A.Z showed marked differences in their gene expression pattern and were distinguished by compromised DNA damage response. Thus, interactions involving a short H2A.Z peptide chain simultaneously determine the stability and accessibility features of chromatin involving the nucleosomes containing this histone variant and the localization of these large chromatin regions in the nucleus. Our data suggest that H2A.Z can function in both heterochromatic and in euchromatic scenarios depending on the molecular interactions involving its C-terminal unstructured tail, shedding light on the enigmatic double-faced character of this histone variant.

In Situ Photoluminescence of Colloidal Quantum Dots During Gas Exposure—The Role of Water and Reactive Atomic Layer Deposition Precursors

2019 ◽  
Vol 11 (29) ◽  
pp. 26277-26287 ◽  
Author(s):  
Jakob Kuhs ◽  
Andreas Werbrouck ◽  
Natalia Zawacka ◽  
Emile Drijvers ◽  
Philippe F. Smet ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Colloidal Quantum Dots ◽  
Layer Deposition ◽  
Gas Exposure

In Situ Rheed and Magneto-Optic Study of Ultrathin Cobalt Films on (111) Gold Substrate: Effect of a Metallic Overlayer

1993 ◽  
Vol 313 ◽  
Author(s):  
Ould-Mahfoud S ◽  
Megy R. ◽  
Bardou N. ◽  
Bartenlian B. ◽  
Beauvillain P. ◽  
...  
Keyword(s):  
Coercive Force ◽  
Magnetic Anisotropy ◽  
Kerr Effect ◽  
Effect Study ◽  
Ultrathin Film ◽  
Substrate Effect ◽  
Gold Substrate ◽  
Cobalt Films ◽  
Magneto Optic

ABSTRACTWe present a comparative in situ RHEED and Polar Magneto-optic Kerr Effect study of the first stages of the growth of a Au overlayer on top of a (111) Co ultrathin film. Drastic behaviours are evidenced on the RHEED diagram, Magnetic anisotropy and coercive force, around 1,5 ML of Au coverage.

Sign in / Sign up

Export Citation Format

Share Document