Localized canting model for substituted ferrimagnets. I. Singly substituted YIG systems

1970 ◽  
Vol 48 (23) ◽  
pp. 2857-2867 ◽  
Author(s):  
A. Rosencwaig
Keyword(s):  
Experimental Data ◽  
Magnetic Properties ◽  
Statistical Model ◽  
Magnetic Moments ◽  
Exchange Parameter ◽  
New Model ◽  
Model Based ◽  
Curie Temperatures ◽  
Good Agreement

A statistical model based on the concept of localized canting, originally proposed by Geller and coworkers, is developed to account for the magnetic properties of substituted ferrimagnets. This model is used to determine the exchange parameter ratios Jdd/Jdd and Jaa/Jad in YIG systems by evaluating the magnetic moments and Curie temperatures of two classes of singly substituted YIG over the entire substitution range. Good agreement with experimental data is obtained with the physically reasonable exchange parameter ratios of [Formula: see text] and Jaa/Jad *~ 0.07. It is also shown that both the Yafet-Kittel and the Nowik models may be regarded as particular limiting cases of the new model.

Modeling the Magnetic Properties of La0.62Er0.05Ba0.33Fe0.2Mn0.8O3: Mean-Field Study and Bean Rodbell Model

2020 ◽  
Vol 17 (4) ◽  
pp. 1571-1575
Author(s):  
Samia Yahyaoui ◽  
Amel Abassi ◽  
Mounira Abassi
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Magnetic Properties ◽  
Mean Field ◽  
Total Momentum ◽  
Exchange Parameter ◽  
Brillouin Function ◽  
The Mean ◽  
Good Agreement ◽  
Second Order Phase Transition

The Brillouin function, the phase transition and the related magnetic properties in La0.62Er0.05Ba0.33Fe0.2Mn0.8O3 perovskite have been studied using Bean-Rodbell model. The Brillouin function allows determining the total momentum J and the mean filed exchange parameter λ of the perovskite. The mean-filed equation draws the system to second order phase transition. These constants were used to stimulate the experimental isotherms M (H, T) by meanfield theory. The predicted results are compared to the available experimental data. It is noted that a good agreement has been found, with minor discrepancies, between theoretical and experimental data.

Analysis and Validation of Cutting Forces Prediction Models in Micromachining

2006 ◽  
Vol 526 ◽  
pp. 13-18 ◽  
Author(s):  
H. Perez ◽  
Antonio Vizan Idoipe ◽  
J. Perez ◽  
J. Labarga
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Cutting Forces ◽  
Prediction Models ◽  
Precision Machining ◽  
New Model ◽  
Proposed Model ◽  
On Line ◽  
Machine Control ◽  
Good Agreement

Many investigations have been developed related to precision machining with features in the millimetre scale. In this paper different cutting force models for micromilling are analyzed and compared. A new model based on specific cutting force that also considers run-out errors has been developed. The estimated cutting forces obtained with this model had good agreement with the experimental data. Also, the proposed model allows to be implemented within the machine control for the on-line optimization of the micromilling process.

Statistical and Theoretical Models of Ingestion Through Turbine Rim Seals

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Kunyuan Zhou ◽  
Simon N. Wood ◽  
J. Michael Owen
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Flow Parameter ◽  
Likelihood Estimation ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Data Points ◽  
Effects Of Rotation ◽  
Effectiveness Data ◽  
Good Agreement

In recent papers, orifice models have been developed to calculate the amount of ingestion, or ingress, that occurs through gas-turbine rim seals. These theoretical models can be used for externally induced (EI) ingress, where the pressure differences in the main gas path are dominant, and for rotationally induced (RI) ingress, where the effects of rotation in the wheel space are dominant. Explicit “effectiveness equations,” derived from the orifice models, are used to express the flow rate of sealing air in terms of the sealing effectiveness. These equations contain two unknown terms: Φmin, a sealing flow parameter, and Γc, the ratio of the discharge coefficients for ingress and egress. The two unknowns can be determined from concentration measurements in experimental rigs. In this paper, maximum likelihood estimation is used to fit the effectiveness equations to experimental data and to determine the optimum values of Φmin and Γc. The statistical model is validated numerically using noisy data generated from the effectiveness equations, and the simulated tests show the dangers of drawing conclusions from sparse data points. Using the statistical model, good agreement between the theoretical curves and several sets of previously published effectiveness data is achieved for both EI and RI ingress. The statistical and theoretical models have also been used to analyze previously unpublished experimental data, the results of which are included in separate papers. It is the ultimate aim of this research to apply the effectiveness data obtained at rig conditions to engine-operating conditions.

SPECIFIC HEAT OF UPd2Al3

1993 ◽  
Vol 07 (01n03) ◽  
pp. 38-41 ◽  
Author(s):  
R. J. RADWAŃSKI ◽  
J. J. M. FRANSE
Keyword(s):  
Magnetic Properties ◽  
Energy Level ◽  
Specific Heat ◽  
Ground State ◽  
Exchange Parameter ◽  
State Function ◽  
Hexagonal Symmetry ◽  
Energy Level Scheme ◽  
Schottky Type ◽  
Good Agreement

Particularities in the specific heat of UPd 2 Al 3, a λ-type of peak with a maximum at 14.5 K and a Schottky-type of peak with a broad maximum at 55 K, has been attributed to the 5f-subsystem of the U atoms. The U-5f contribution has been found to be described surprisingly well within a single-ion Hamiltonian that includes the charge multipolar (CMP) interactions and the antiferromagnetic (AF) exchange interaction between the U 3+ ions. The AF exchange parameter and the full set of the CMP parameters associated with the hexagonal symmetry have been evaluated. The energy-level scheme (ELS) of this Kramers ion is constructed. The ground-state function Γ8 of the 5f 3 electrons is highly anisotropic. This state results from higher-order charge multipolar interactions. Magnetic properties resulting from this scheme including the metamagnetic-like transition at 18 T, the strongly-reduced value for the U-ion moment and its field dependence are found to be in good agreement with experimental observations.

Magnetic Properties of Compounds RE2Cu2Mg (RE = Y, La, Pr, Nd)

2003 ◽  
Vol 58 (6) ◽  
pp. 497-500 ◽  
Author(s):  
Gunter Kotzybaa ◽  
Ratikanta Mishrab ◽  
Rainer Pöttgena
Keyword(s):  
Magnetic Properties ◽  
High Frequency ◽  
Remanent Magnetization ◽  
Magnetic Transition ◽  
Magnetic Moments ◽  
Temperature Dependent ◽  
Furnace Temperature ◽  
Pauli Paramagnetism ◽  
Magnetization Behavior ◽  
Curie Temperatures

The Mo2FeB2 type magnesium intermetallics RE2Cu2Mg (RE = Y, La, Pr, Nd) were synthesized from the elements by reactions in sealed tantalum tubes in a high-frequency furnace. Temperature-dependent magnetic susceptibility measurements of Y2Cu2Mg and La2Cu2Mg indicate Pauli paramagnetism. Pr2Cu2Mg and Nd2Cu2Mg show Curie-Weiss behaviour with experimental magnetic moments of 3.67(2) μB/Pr and 3.47(2) μB/Nd, respectively. Both compounds are ordered ferromagnetically at Curie temperatures of 12.0(5) (Pr2Cu2Mg) and 43.0(5) K (Nd2Cu2Mg). Pr2Cu2Mg shows a very complex magnetization behavior with an additional magnetic transition around 2.5 T. The neodymium compound shows a pronounced square loop behavior in the magnetization at 4.5 K with a high remanent magnetization of 1.55(1) μB/Nd atom and a coercive field of 0.31(1) T.

Magnetic Properties of PrхY1-xFe3(BO3)4

2015 ◽  
Vol 233-234 ◽  
pp. 360-363
Author(s):  
A.I. Pankrats ◽  
A.A. Demidov ◽  
D.A. Velikanov ◽  
V.I. Tugarinov ◽  
V.L. Temerov
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Magnetic Properties ◽  
Rare Earth ◽  
Field Model ◽  
Field Approximation ◽  
Magnetization Curves ◽  
Extensive Experimental Data ◽  
Theory And Experiment ◽  
Good Agreement

The magnetic properties of trigonal PrxY1-xFe3(BO3)4 compound have been investigated. Anomalies on the magnetization curves induced by a magnetic field are observed for each composition. The calculations were performed using a molecular-field approximation and a crystal-field model for the rare-earth subsystem. Extensive experimental data on the magnetic properties of PrxY1-xFe3(BO3)4 have been interpreted and good agreement between theory and experiment has been achieved.

IRON INFLUENCE ON OPTICAL AND MAGNETIC PROPERTIES OF LEAD-BISMUTHATE GLASSES

2003 ◽  
Vol 17 (05n06) ◽  
pp. 235-244
Author(s):  
V. SIMON ◽  
R. POP ◽  
N. N. PUŞCAŞ
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moments ◽  
Magnetic Interaction ◽  
Infrared Range ◽  
Matrix Formalism ◽  
Iron Ions ◽  
Density Matrix Formalism ◽  
Optical And Magnetic Properties ◽  
Experimental Values ◽  
Curie Temperatures

Results concerning the structural, optical and magnetic properties of x Fe 2 O 3 · (100 - x)[3 Bi 2 O 3 · 2 PbO ] glasses (0 = x = 20 mol%) are reported. The transparence in the infrared range was investigated. The homogeneous absorption cross section was determined from the optical absorption spectra using the density matrix formalism of the McCumber theoretical model. From the temperature dependence of reciprocal magnetic susceptibility, negative paramagnetic Curie temperatures have been found suggesting the antiferromagnetic nature of the magnetic interaction between the iron ions in the studied samples. The iron ions occur both in the (II) and (III) valence state. The Fe 2+/ Fe 3+ ratio was determined from the experimental values of the magnetic moments for all samples. The glass transition temperature with increasing Fe 2 O 3 content was also investigated.

scholarly journals Магнитные свойства и природа магнитного состояния интеркалированных соединений Cr-=SUB=-x-=/SUB=-MoSe-=SUB=-2-=/SUB=-

2019 ◽  
Vol 61 (3) ◽  
pp. 472
Author(s):  
В.Г. Плещев ◽  
Н.В. Селезнева
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Low Temperature ◽  
Magnetic Moments ◽  
Ferromagnetic State ◽  
Paramagnetic Region ◽  
Temperature Dependences ◽  
Ferromagnetic Interactions ◽  
Curie Temperatures ◽  
Hysteresis Phenomena

AbstractThis is a pioneering work on the synthesis of molybdenum diselenides intercalated by chromium atoms. Their magnetic properties are studied at various intercalant concentrations, temperatures, and magnetic fields. The temperature dependences of effective magnetic moments and positive paramagnetic Curie temperatures in the paramagnetic region evidence the feasible ferromagnetic interactions between intercalated atoms. The existence of low-temperature ferromagnetic state in Cr_ x МоSe_2 is confirmed by hysteresis phenomena in temperature and field dependences of magnetization and magnetic susceptibility.

Magnetic properties of rare earth chromium borates at high temperatures

2021 ◽  
pp. 166-170
Author(s):  
O.K. Kuvandikov ◽  
◽  
N.I. Leonyuk ◽  
V.V. Malsev ◽  
M.M. Kuzmin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Temperature Dependence ◽  
High Temperatures ◽  
Wide Temperature Range ◽  
Magnetic Moments ◽  
Chemical Formula ◽  
Temperature Range ◽  
Curie Temperatures

Temperature dependence of the magnetic susceptibility has been studied for rare-earth borates NdCr3(BO3)4, SmCr3(BO3)4 and LuCr3(BO3)4 by the Faradey method in the wide temperature range (300-1200 K). The dependence for each phase follows the Curi - Weis law. The Curie temperatures, Neel temperatures and magnetic moments corresponding to the chemical formula of the crystals, have been found.

A Compact Model for Spherical Rough Contacts

2005 ◽  
Vol 127 (4) ◽  
pp. 884-889 ◽  
Author(s):  
M. Bahrami ◽  
M. M. Yovanovich ◽  
J. R. Culham
Keyword(s):  
Experimental Data ◽  
Pressure Distribution ◽  
Contact Pressure ◽  
Compact Model ◽  
Elastic Contact ◽  
Smooth Surfaces ◽  
New Model ◽  
Maximum Contact ◽  
Good Agreement ◽  
Key Parameter

A new model is developed that considers the effect of roughness on the elastic contact of spherical bodies. A general pressure distribution is proposed that encompasses the contact of rough spheres and yields the Hertzian theory for ideally smooth surfaces. A new parameter, nondimensional maximum contact pressure, is introduced and it is shown that this is the key parameter that controls the contact. The results of the present study are presented in the form of compact relationships. These relationships are compared against the experimental data collected by others and good agreement is observed.

Sign in / Sign up

Export Citation Format

Share Document