THE EFFECTS OF PLASTIC DEFORMATION ON MAGNETIC PROPERTIES OF POLYCRYSTALLINE METALS

1951 ◽  
Vol 29 (1) ◽  
pp. 21-31
Author(s):  
Ursula M. Martius
Keyword(s):  
Plastic Deformation ◽  
Magnetic Properties ◽  
Magnetic Flux ◽  
Crystallographic Orientation ◽  
Ferromagnetic Behavior ◽  
Polycrystalline Metal ◽  
Polycrystalline Metals ◽  
Ferromagnetic Domains ◽  
Polycrystalline Body ◽  
Crystal Boundaries

Most of the laws of the ferromagnetic behavior of metals and alloys were derived from studies of single crystals. In order to apply these laws to polycrystalline metals the effect of the crystallographic composition of the polycrystalline body has to be taken into account. For this purpose the concept of a "closed flux shell" as a fundamental quality of polycrystalline metal is put forward on the basis of the following trend of thought:One of the most important factors determining the size and arrangement of ferromagnetic domains in a single crystal is the tendency to close the magnetic flux throughout the specimen by a suitable arrangement of these domains. The size of the crystal defines the limits within which the flux can be closed. In a polycrystalline metal, a "crystal" is defined as a region of one crystallographic orientation separated by crystal boundaries from neighboring regions of different orientation. The corresponding unit, as far as ferromagnetic properties are concerned, will be a closed flux shell which may contain many domains but is always a region of closed magnetic flux. Neighboring regions, having different crystallographic orientation, will each also consist of a closed magnetic flux shell. Crystal boundaries are regarded as lattice discontinuities which separate regions of different orientation and at the same time separate different closed flux shells.The consequences of this model and experimental evidence supporting it are discussed. An explanation of the effect of plastic deformation on magnetic properties is suggested by considering the changes in the size of the closed flux shell which will occur during plastic deformation.

Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

2020 ◽  
Vol 16 (4) ◽  
pp. 655-666
Author(s):  
Mona Rekaby
Keyword(s):  
Magnetic Properties ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Structural Defects ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Antiferromagnetic Ordering ◽  
Doped Zno ◽  
Co Doped

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

scholarly journals Influence of plastic deformation on the magnetic properties of Heusler MnAu2Al

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Emily E. Levin ◽  
Daniil A. Kitchaev ◽  
Yolita M. Eggeler ◽  
Justin A. Mayer ◽  
Piush Behera ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Magnetic Properties

scholarly journals The effect of pressure and alloying on half-metallicity of quaternary Heusler compounds CoMnYZ (Z = Al, Ga, and In)

2016 ◽  
Vol 34 (4) ◽  
pp. 905-915 ◽  
Author(s):  
M. Rahmoune ◽  
A. Chahed ◽  
A. Amar ◽  
H. Rozale ◽  
A. Lakdja ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Heusler Alloys ◽  
Band Gaps ◽  
Ferromagnetic Behavior ◽  
Full Potential ◽  
Energy Bands ◽  
Half Metallicity ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

AbstractIn this work, first-principles calculations of the structural, electronic and magnetic properties of Heusler alloys CoMnYAl, CoMnYGa and CoMnYIn are presented. The full potential linearized augmented plane waves (FP-LAPW) method based on the density functional theory (DFT) has been applied. The structural results showed that CoMnYZ (Z = Al, Ga, In) compounds in the stable structure of type 1+FM were true half-metallic (HM) ferromagnets. The minority (half-metallic) band gaps were found to be 0.51 (0.158), 0.59 (0.294), and 0.54 (0.195) eV for Z = Al, Ga, and In, respectively. The characteristics of energy bands and origin of minority band gaps were also studied. In addition, the effect of volumetric and tetragonal strain on HM character was studied. We also investigated the structural, electronic and magnetic properties of the doped Heusler alloys CoMnYGa1−xAlx, CoMnYAl1−xInx and CoMnYGa1−xInx (x = 0, 0.25, 0.5, 0.75, 1). The composition dependence of the lattice parameters obeys Vegard’s law. All alloy compositions exhibit HM ferromagnetic behavior with a high Curie temperature (TC).

Formation of Cr-rich Nano-clusters and Columns in (Zn,Cr)Te Grown by MBE

2009 ◽  
Vol 1183 ◽  
Author(s):  
Yôtarõ Nishio ◽  
Kôichirô Ishikawa ◽  
Shinji Kuroda ◽  
Masanori Mitome ◽  
Yoshio Bando
Keyword(s):  
Magnetic Properties ◽  
Substrate Temperature ◽  
Crystallographic Orientation ◽  
Vertical Direction ◽  
Growth Conditions ◽  
Chemical Analyses ◽  
Mbe Growth ◽  
One Dimensional ◽  
X Ray ◽  
Cr Content

AbstractThe correlation between the Cr aggregation and magnetic properties are investigated for the series of Zn1-xCrxTe films grown by MBE with a systematic variation of growth conditions. Structural and chemical analyses using TEM and energy-dispersive X-ray spectroscopy (EDS) reveal that the crystallinity and the Cr distribution change significantly with the substrate temperature during the MBE growth. For a relatively low average Cr content x ≅ 0.05, it is found that the crystal quality is improved with the increase of the substrate temperature. For a higher average Cr content x ≅ 0.2, the shape of Cr-rich regions is transformed from isolated clusters into one-dimensional nanocolumns with the increase of the substrate temperature. The direction of the nanocolumn formation changes depending on the crystallographic orientation of the grown films. In the magnetization measurements, anisotropic magnetic properties are observed in the films in which Cr-rich nanocolumns are formed in the vertical direction, depending on the relation between the direction of the nanocolumns and the applied magnetic fields.

Percolation Effects in the Mechanical Properties of Granular Ni-A12O3 thin films

1990 ◽  
Vol 195 ◽  
Author(s):  
T.E. Schlesinger ◽  
A. Gavrin ◽  
R.C. Cammarata ◽  
C.-L. Chien
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Magnetic Properties ◽  
Percolation Threshold ◽  
Volume Fraction ◽  
Electrical And Magnetic Properties ◽  
Low Load

ABSTRACTThe mechanical properties of sputtered Ni-Al2O3 granular thin films were investigated by low load microharaness testing. It was found that the microhardness of these films displayed a percolation threshold at a nickel volume fraction of about 0.6, below which the hardness is greatly enhanced. This behavior is qualitatively similar to the electrical and magnetic properties of these types of films. A percolation threshold in hardness can be understood as due to a change in the mechanism for plastic deformation.

Assessment of Magnetic Properties between Fe and Ni Doped ZnO Nanoparticles Synthesized by Microwave Assisted Synthesis Method

2021 ◽  
Vol 317 ◽  
pp. 119-124
Author(s):  
Sabiu Said Abdullahi ◽  
Garba Shehu Musa Galadanci ◽  
Norlaily Mohd Saiden ◽  
Josephine Ying Chyi Liew
Keyword(s):  
Magnetic Properties ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Synthesis Method ◽  
Dilute Magnetic Semiconductors ◽  
High Coercivity ◽  
Microwave Assisted Synthesis ◽  
Ferromagnetic Behavior ◽  
Microwave Assisted ◽  
Doped Zno

The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.

Magnetic properties of two-dimensional Josephson networks: Self-organized criticality in magnetic flux dynamics

JETP Letters ◽  
2000 ◽  
Vol 72 (1) ◽  
pp. 26-29 ◽  
Author(s):  
S. M. Ishikaev ◽  
É. V. Matizen ◽  
V. V. Ryazanov ◽  
V. A. Oboznov ◽  
A. V. Veretennikov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Flux ◽  
Two Dimensional ◽  
Flux Dynamics ◽  
Self Organized ◽  
Self Organized Criticality

scholarly journals Anisotropy of Magnetic Properties in Non-oriented Electrical Steel Sheets

1989 ◽  
Vol 11 (2-4) ◽  
pp. 159-170 ◽  
Author(s):  
M. Shiozaki ◽  
Y. Kurosaki
Keyword(s):  
Magnetic Properties ◽  
Magnetic Induction ◽  
Crystallographic Orientation ◽  
Electrical Steel ◽  
Core Loss ◽  
Fluorescent Lamp ◽  
Steel Sheets ◽  
The Core ◽  
Texture Change ◽  
Electrical Steel Sheets

The anisotropy of magnetic properties in non-oriented electrical steel sheets can be evaluated by measuring Epstein specimens in the radial directions. The magnetic properties measured on ring cores are practically equal to the approximate values of magnetic properties determined by Epstein specimens in the radial directions. Non-oriented electrical steel sheets with anisotropy are not desirable for motors but are suitable for transformers and fluorescent lamp ballasts. The core loss and magnetic induction as measured with ring specimens are better with non-oriented electrical steel sheets with anisotropy than with non-oriented electrical steel sheets with random crystallographic orientation. This phenomenon depends on the texture change of the product.

Sign in / Sign up

Export Citation Format

Share Document