APPLIED SURFACE AND PROPERTIES ANALYSES OF Co-BASED NANOPARTICLE THIN FILMS FOR PERMANENT MAGNETS

2006 ◽  
Vol 05 (06) ◽  
pp. 821-826
Author(s):  
XIANG WANG ◽  
ZUOYI LI
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Magnetic Layer ◽  
Perpendicular Anisotropy ◽  
Transition Metal Alloy ◽  
Lattice Matching ◽  
Fine Grain ◽  
Magnetic Layers

The SmCoSi/Cr layers were sputtered and annealed at 500°C for 25 min in pure N 2 atmosphere. The optimum value of coercivity of 4.6 kOe and extremely fine grain size of average grain diameter 6.5 nm, or small switching volume V* of 2.6 × 10-19 cm 3 were obtained. Partial Sm substituted by Tb will directly affect the magnetic properties. The ( Sm 0.32 Tb 0.68) Co 2 Si 3/ Cr layers with perpendicular anisotropy have been investigated. Their values of magnetization Ms as high as 402 emu/cm3 and coercivity Hc above 5.5 kOe at room temperature were gotten. These films are the ferri-magnetical structure of the rare earth-transition metal alloy. The microstructures and lattice matching media were examined, and the mechanisms of decoupling intergrains within the same magnetic layer, and among magnetic layers have been analyzed.

Microstructure and Properties of (Tb,Sm)CoSi/Cr Series Thin Films for Permanent Magnets

2007 ◽  
Vol 121-123 ◽  
pp. 267-270 ◽  
Author(s):  
X. Wang ◽  
Z.Y. Li ◽  
X. Yu ◽  
S. Su ◽  
J. Li
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Permanent Magnets ◽  
Magnetic Layer ◽  
Lattice Matching ◽  
Microstructure And Properties ◽  
N2 Atmosphere ◽  
Magnetic Layers

The microstructures and properties of (Tb,Sm)CoSi/Cr series films have been investigated. All the samples were sputtered and annealed at 500 °C for 25 min in pure N2 atmosphere, and their microstructures and properties were examined. The effect on the magnetic properties of partial Sm substituted by Tb is discussed. The lattice matching media were examined. And the mechanisms of interactions among the grains and between the magnetic layers have been analyzed by comparing multi magnetic layer with the mono magnetic layer.

Room temperature strength of β-sialon (z=0.5) fabricated using fine grain size alumina powder

2001 ◽  
Vol 21 (9) ◽  
pp. 1269-1272 ◽  
Author(s):  
Kazushi Kishi ◽  
Seiki Umebayashi ◽  
Eiji Tani ◽  
Kazuhisa Shobu ◽  
Yanping Zhou
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Alumina Powder ◽  
Fine Grain ◽  
Room Temperature Strength

Thermal Stability of Magnetic Properties in Dehydrogenated Triarylmethane Resins

1989 ◽  
Vol 173 ◽  
Author(s):  
Michiya Otani ◽  
Sugio Otani
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
The Stability ◽  
Thermal Stability Of

ABSTRACTThe stability of the magnetic properties of dehydrogenated triaryl-methane resins was investigated both at room temperature and at elevated temperatures. A magnetic property different from that reported in a previous paper was found in the course of studying the reproducibility of synthesis. This new property was examined through a mechanical response of the resins to a set of permanent magnets.

Adjacent Layer Composition Effects on Fetbco Thin Film Magnetic Properties

1995 ◽  
Vol 384 ◽  
Author(s):  
Michael B. Hintz
Keyword(s):  
Magnetic Properties ◽  
Ion Beam ◽  
Magnetic Layer ◽  
Magnetic Behavior ◽  
Relative Magnitude ◽  
Adjacent Layer ◽  
Energy Product ◽  
Magnetic Layers ◽  
20 Nm ◽  
Layer Composition

ABSTRACTThe magneto-optical (MO) layer in current rare earth-transition metal (RE-TM) based MO recording media is typically 20 nm to 60 nm thick. It has been suggested, however, that media structures employing a multiplicity of thinner MO layers may be advantageous, e.g., for multilevel recording applications [1] or media noise reduction [2]. As magnetic layer thickness is reduced, interactions among magnetic layers and adjacent materials can have an increasingly large influence on magnetic properties; in many instances, these interactions can dominate the observed magnetic behavior.As a means of studying MO layer - adjacent layer interactions, we have used thin (≈3 nm) films of several materials to separate single 24 nm thick ion-beam-deposited FeTbCo layers into N thinner layers of 24/N nm thickness (N × 24/N). As N increases, the FeThCo magnetic properties generally change; however, the relative magnitude of the changes is strongly dependent upon the adjacent layer composition. Magnetization (Ms), energy product (MsHc) at 30 C and Curie temperature data for 1 × 24 nm structures and 6 × 4 nm structures are compared and discussed for specimens employing SiCx, Six, YOx, HfOx, Si and SiOx adjacent layer materials.

Influence of Milling Time on Magnetic Properties and Microstructure of Sintered Nd-Fe-B Based Permanent Magnets

2018 ◽  
Vol 930 ◽  
pp. 445-448
Author(s):  
R.G.T. Fim ◽  
M.R.M. Silva ◽  
S.C. Silva ◽  
Julio Cesar Serafim Casini ◽  
P.A.P. Wendhausen ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Permanent Magnets ◽  
Milling Time ◽  
Maximum Energy ◽  
Inhomogeneous Distribution ◽  
Maximum Energy Product ◽  
Grain Sizes ◽  
Energy Product

In this paper, the effect of the grain size on sintered Nd-Fe-B based permanent magnets was investigated. In order, the magnets were produced by different milling times at 200 rpm and then vacuum sintered at 1373 K for 60 minutes followed by cooling outside the furnace. The magnets either produced by lower and higher milling times (30 and 75 minutes) exhibited lower remanence and coercivity, due the inhomogeneous distribution of the grain sizes. The magnet produced by intermediary milling time (45 minutes) exhibited the highest properties among all samples, with remanence of 1.06 T, coercivity of 891.3 KA.m-1, maximum energy product of 211 KJ.m3and a squareness factor equal 0.92.

Synthesis, Microstructure and Magnetic Properties of Nanocrystalline Ni-Zn Ferrite by a Modified Wet Chemical Method

2008 ◽  
Vol 368-372 ◽  
pp. 594-597
Author(s):  
Yin Liu ◽  
Tai Qiu
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Wet Chemical Method ◽  
Specific Saturation Magnetization ◽  
Random Anisotropy ◽  
Zn Ferrite ◽  
Wet Chemical ◽  
Critical Grain Size ◽  
Microstructure And Magnetic Properties

Nanocrystalline Ni1-xZnxFe2O4 ferrites with 0 ≤ x ≤ 1 were prepared by sprayingcoprecipitation method. The microstructure was investigated by TG-DSC, XRD, SEM, TEM and BET. Magnetic properties were measured with vibrating sample magnetometer at room temperature. The results showed that uniform and fine nanocrystalline Ni1-xZnxFe2O4 ferrites are obtained. The grain size of sample calcined at 600°C for 1.5h is about 30nm. There are a few agglomerates with average sizes below 100nm. The specific saturation magnetization, Ms, of the sample increases with increasing Zn2+ concent x at room temperature, and the maximum Ms is 66.8 A·m2·kg-1 as the Zn2+ content x is around 0.5mol. As calcining temperature increased from 400°C to 1050°C, the Ms of Ni0.5Zn0.5Fe2O4 ferrite increases from 40.2 A·m2·kg-1 to 75.6 A·m2·kg-1. The coercivity maximum is about 5.97 kA·m-1 as its critical grain size is about 62.0nm. The relation between coercivity and grain size for nanocrystalline Ni0.5Zn0.5Fe2O4 ferrite may be explained based on random anisotropy theory.

The Fatigue Behavior of γ/α2 Titanium Aluminides

1990 ◽  
Vol 213 ◽  
Author(s):  
W.E. Dowling ◽  
W.T. Donlon ◽  
J.E. Allison
Keyword(s):  
Grain Size ◽  
Fatigue Life ◽  
Room Temperature ◽  
High Cycle Fatigue ◽  
Titanium Aluminides ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Fine Grain

ABSTRACTAxial load controlled high cycle fatigue experiments were conducted on the γ/α2 alloy, Ti-48A1-1V-0.2C (at%), at 23 and 815°C. Four different microstructures, produced through thermomechanical processing, were evaluated to examine the influence of grain size and α2 content on fatigue behavior. The load controlled fatigue life was significantly reduced by increasing grain size and unaffected by α2 content at both 23 and 815°C. Although, α2 content did not greatly influence high cycle fatigue life, the room temperature crack initiation and fast fracture was changed from transgranular to partially intergranular as the volume fraction of α2 was reduced in the fine grain size material. The fatigue strength at 107 cycles (FS) to ultimate tensile strength (UTS) ratio was 0.8 to 0.9 at 23°C and 0.5 to 0.6 at 815°C for all microstructures examined. Low tensile ductility, high work hardening rate and the difficulty in forming strain local-izations all aided the high FS/UTS ratio. The dislocation microstructures produced by fatigue at room temperature were examined in the fine grained high α2 (ductile) microstructure. They consisted of loop patches of all <110] regular dislocations without any <101] or <011] super dislocations because of the large difference in CRSS for these dislocation. The inability to nucleate and move superdislocations inhibited the formation of persistent slip bands as is often found in high and intermediate stacking fault FCC metals.

scholarly journals Magnetic Properties of Mn-Zn Ferrites Having Fine Grain Size.

1994 ◽  
Vol 41 (2) ◽  
pp. 201-204
Author(s):  
Yasuharu Miyoshi ◽  
Naoyuki Okamoto ◽  
Keisuke Kageyama
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Fine Grain

Shock Consolidation of Sm-Fe-N Magnetic Powders and Magnetic Properties

2004 ◽  
Vol 449-452 ◽  
pp. 1037-1040 ◽  
Author(s):  
Akira Chiba ◽  
K. Ooyabu ◽  
Yasuhiro Morizono ◽  
Tomoyuki Maeda ◽  
Shinya Sugimoto ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
High Performance ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Anisotropy Field ◽  
Temperature Anisotropy ◽  
Bulk Materials ◽  
Shock Consolidation ◽  
Explosive Consolidation ◽  
Processing Techniques

Sm2Fe17Nx compound is a prospective candidate as a material for high performance permanent magnets because of its good intrinsic magnetic properties with a Curie temperature of 747K, a room-temperature anisotropy field of 14T and a room-temperature saturation magnetization of 1.5T. However, Sm2Fe17Nx compound decomposes to -Fe and Sm nitride above 873K and conventional powder metallurgy processing techniques fail to meet the processing requirements. Shock consolidation is a viable alternative to process this compound. Fully dense Sm2Fe17Nx bulk materials were fabricated by cylindrical explosive consolidation technique using water as a pressure transmitting medium. Explosive consolidation is performed under cold state and fully dense materials can be obtained without any degradation of the characteristics of the powder states. Sound compacts were obtained without any cracks or teas, and the value of (BH)max of Sm2Fe17Nx compact is 23.8 MGOe.

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