Grain separation enhanced magnetic coercivity in Pt/Co multilayers.

1993 ◽  
Vol 51 ◽  
pp. 1038-1039 ◽  
Author(s):  
G.A. Bertero ◽  
R. Sinclair
Keyword(s):  
Remanent Magnetization ◽  
Strong Influence ◽  
Uniaxial Anisotropy ◽  
Magnetic Coupling ◽  
Recording Media ◽  
Magnetic Media ◽  
Signal To Noise ◽  
Out Of Plane ◽  
Longitudinal Recording ◽  
The Relationship

Pt/Co multilayers displaying perpendicular (out-of-plane) magnetic anisotropy and 100% perpendicular remanent magnetization are strong candidates as magnetic media for the next generation of magneto-optic recording devices. The magnetic coercivity, Hc, and uniaxial anisotropy energy, Ku, are two important materials parameters, among others, in the quest to achieving higher recording densities with acceptable signal to noise ratios (SNR). The relationship between Ku and Hc in these films is not a simple one since features such as grain boundaries, for example, can have a strong influence on Hc but affect Ku only in a secondary manner. In this regard grain boundary separation provides a way to minimize the grain-to-grain magnetic coupling which is known to result in larger coercivities and improved SNR as has been discussed extensively in the literature for conventional longitudinal recording media.We present here results from the deposition of two Pt/Co/Tb multilayers (A and B) which show significant differences in their coercive fields.

Influence of exchange on signal-to-noise ratio in longitudinal recording media

2002 ◽  
Vol 91 (5) ◽  
pp. 3129-3138 ◽  
Author(s):  
O. Chubykalo ◽  
B. Lengsfield ◽  
J. Kaufman ◽  
B. Jones
Keyword(s):  
Signal To Noise Ratio ◽  
Recording Media ◽  
Signal To Noise ◽  
Longitudinal Recording ◽  
Noise Ratio

Microstructure and magnetic Structure of Co-based thin-film recording medium

1993 ◽  
Vol 51 ◽  
pp. 1012-1013
Author(s):  
M. Futamoto ◽  
Y. Honda ◽  
N. Inaba ◽  
Y. Matsuda ◽  
M. Suzuki
Keyword(s):  
Thin Film ◽  
Layered Medium ◽  
Average Distance ◽  
Magnetic Coupling ◽  
Film Plane ◽  
Recording Medium ◽  
Plan View ◽  
Sem Micrograph ◽  
Longitudinal Recording ◽  
The Relationship

Knowledge of the relationship between microstructure and microscopic magnetization configuration is strongly required to improve Co-based thin film media. The purpose of this paper is to report some of these properties measured for a thin film longitudinal recording medium and to discuss their inter-relationship.Figure 1 shows an SEM micrograph of fractured cross-section of CoCrPt/CoCrPtSi dual-layered medium which was used to demonstrate the feasibility of 2 Gb/in2 magnetic recording. The Cr underlayer is used to control the orientation, size, and distribution of magnetic crystals. Magnetic crystal grains, whose size ranges between 20-30nm, form chain-like clusters consisting of several crystals as shown in the plan-view TEM micrograph(Fig.2). Neighboring clusters are separated physically with an average distance of 3nm. Magnetic separation among magnetic crystals and/or clusters is important to reduce the medium noise which is related to magnetic coupling between crystals. The crystalline easy axes of the grains are randomly oriented in the film plane.

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

scholarly journals A van der Waals antiferromagnetic topological insulator with weak interlayer magnetic coupling

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chaowei Hu ◽  
Kyle N. Gordon ◽  
Pengfei Liu ◽  
Jinyu Liu ◽  
Xiaoqing Zhou ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Surface States ◽  
Magnetic Coupling ◽  
Anomalous Hall Effect ◽  
Saturation Field ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Ideal System ◽  
Out Of Plane ◽  
Weak Interlayer ◽  
Quantum Phenomena

AbstractMagnetic topological insulators (TI) provide an important material platform to explore quantum phenomena such as quantized anomalous Hall effect and Majorana modes, etc. Their successful material realization is thus essential for our fundamental understanding and potential technical revolutions. By realizing a bulk van der Waals material MnBi4Te7 with alternating septuple [MnBi2Te4] and quintuple [Bi2Te3] layers, we show that it is ferromagnetic in plane but antiferromagnetic along the c axis with an out-of-plane saturation field of ~0.22 T at 2 K. Our angle-resolved photoemission spectroscopy measurements and first-principles calculations further demonstrate that MnBi4Te7 is a Z2 antiferromagnetic TI with two types of surface states associated with the [MnBi2Te4] or [Bi2Te3] termination, respectively. Additionally, its superlattice nature may make various heterostructures of [MnBi2Te4] and [Bi2Te3] layers possible by exfoliation. Therefore, the low saturation field and the superlattice nature of MnBi4Te7 make it an ideal system to investigate rich emergent phenomena.

Overwrite Modulation in Co-Based Thin Film Longitudinal Recording Media

1994 ◽  
Vol 18 (S_1_PMRC_94_1) ◽  
pp. S1_467-470
Author(s):  
Michinobu SUEKANE ◽  
Masao MIYAMURA
Keyword(s):  
Thin Film ◽  
Recording Media ◽  
Longitudinal Recording

Coupled Granular/Continuous Media – Results and Challenges

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2661-2668
Author(s):  
Horia Gavrila ◽  
Doina Elena Gavrila
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Magnetic Recording ◽  
Granular Media ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Theoretical Limit ◽  
Perpendicular Recording ◽  
Perpendicular Magnetic Recording ◽  
Longitudinal Recording

ABSTRACTWhile the most promising longitudinal recording systems cannot surpass the theoretical limit of about 200 Gb/in2 for areal recording density and the demand for higher densities is permanently increasing, the perpendicular magnetic recording constitutes the realistic issue to the longitudinal one. The perpendicular magnetic recording offers significant advantages, the most important being stronger write and read fields, and therefore the use of media of higher anisotropy, smaller grain size, higher signal-to-noise ratio, and a better thermal stability. Unfortunately, the perpendicular recording has to cope some important physical and technological difficulties. To overcome them, many ingenious solutions were proposed. In this paper the coupled granular/continuous (CGC) media, a subtle association of the continuous and, respectively, granular media, are analysed from the viewpoint of their magnetic and recording properties. The challenges and possible improvements of CGC media are discussed.

PENDIDIKAN KEIMANAN ANAK DALAM KELUARGA MENURUT ZAKIAH DARADJAT

2018 ◽  
Vol 1 (2) ◽  
pp. 110-121
Author(s):  
Rivanti Muslimawaty
Keyword(s):  
Qualitative Research ◽  
Research Methods ◽  
Religious Education ◽  
Strong Influence ◽  
Educational Institution ◽  
Qualitative Research Methods ◽  
Human Beings ◽  
The Family ◽  
The Relationship

Many parents do not understand the concept of faith education inchildren. This could be based on an assumption that children are stilltoo young to be educated in matters of faith. Whereas the family, in thiscase the parents, is an educational institution that is directly related tothe child since he was born. So there is a thought that the family isbelieved to have a very strong influence on children’s religiouseducation. This happens because the relationship that exists betweenparents and children for 24 hours is very important in education.Zakiah Daradjat is an education expert who also believes that theimportance of faith education is given to children as early as possible,so the purpose of this study is to find out how Zakiah Daradjat’sthoughts about children’s religious education are in the family. Byusing qualitative research methods, the author seeks to explain theeducation of children’s faith in the family according to ZakiahDaradjat. The author found that Zakiah Daradjat had clear thoughtsabout children’s religious education in the family, which aims to makechildren as human beings, through the six pillars of faith, with methodsof exemplification, habituation, wrong correction, erroneous quarrelsthat occur and reminding the forgotten. The evaluations carried out inthe form of memorization tests, tests of understanding and practice ofworship. This makes Zakiah Daradjat’s thoughts still relevant to beapplied in today’s life and become a reference for psrents, teachers abdother related parties.

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