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.

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.

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.

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.

MAGNETIC BEHAVIOR OF LEAD-BISMUTATE GLASSES CONTAINING TRANSITION METAL ELEMENTS

2001 ◽  
Vol 15 (27) ◽  
pp. 1231-1236 ◽  
Author(s):  
R. POP ◽  
V. SIMON ◽  
I. COSMA ◽  
M. COLDEA
Keyword(s):  
Experimental Data ◽  
Magnetic Susceptibility ◽  
Transition Metal ◽  
Transition Metal Oxides ◽  
Glass Matrix ◽  
Magnetic Behavior ◽  
Magnetic Interaction ◽  
Iron Ions ◽  
Manganese Ions ◽  
Curie Temperatures

The investigated samples are obtained by adding to the 3Bi2O3·2PbO glass matrix the transition metal oxides Fe2O3 or MnO up to 20 mol%. The temperature dependencies of the magnetic susceptibility evidence negative paramagnetic Curie temperatures suggesting the antiferromagnetic nature of the magnetic interaction between the transition metal (TM) ions in the samples studied. According to the magnetic moment values, calculated from the experimental data, the valence state of the iron ions changes from Fe 3+ to Fe 2+ and that of manganese ions from Mn 2+ to Mn 3+ as the concentration x increases from 1 to 20 mol%.

Magnetic Characteristics of RCo7−xZrx Alloys (invited) (R = Sm, Pr, Er, Gd, and Y)

1999 ◽  
Vol 577 ◽  
Author(s):  
M.Q. Huang ◽  
W.E. Wallace ◽  
M.E. Mchenry ◽  
S.G. Sankar ◽  
Qun Chen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Magnetic Moments ◽  
Anisotropy Field ◽  
Experimental Results ◽  
Magnetic Characteristics ◽  
Treatment Conditions ◽  
Experimental Values ◽  
Co Alloys

ABSTRACTA brief review is presented of recent work dealing with the structure and magnetic properties of RCo7−x Zrx alloys (R=Sm, Pr, Er, Gd, and Y). The experimental results obtained are consistent with a model in which Zr atoms partly replace dumbbell Co atoms and play an important role in stabilizing the TbCu7 structure while significantly increasing the anisotropy field (HA). For example, when R=Sm, HA increases from 90 kOe for x=O to 130 kOe for x=0.2 at 300 K, and from 140 kOe for x=0 to 220 kOe for x=0.2 at 10 K. In the case of R=Y and Gd, HA is mainly contributed by the Co sublattice. For R=Y alloys, HA increases from 18 kOe for x=0 to 74 kOe for x=0.2 at 300 K and from 20 kOe for x=0 to 82 kOe for x=0.2 at 10 K. For R=Gd alloys, HA shows the largest enhancement. It increases from 35 kOe for x=0 to 140 kOe for x=0.2 at 300 K and from planar for x=0 to uniaxial with 182 kOe for x=0.2 at 10 K. In general, experimental results are in accord with the theory of Greedan and Rao for anisotropies of R-Co alloys. The magnetic moments for cobalt and rare earth in RCo7−xrx compounds (x=0∼A).2) have been estimated from the experimental values. The results show that they are nearly the same as those in RCo5 or R2Co17. The Co moment is 1.5∼;1.6 μB. Some phase transition phenomenon between RCo5, RCo7, R2Co17and R2Co7at different heat treatment conditions will also be discussed.

Optical And Magnetic Properties Of Rigid Rod Conjugated Molecules

1993 ◽  
Vol 328 ◽  
Author(s):  
P. Wautelet ◽  
J. Le Moigne ◽  
P. Turek
Keyword(s):  
Magnetic Properties ◽  
Optical Properties ◽  
Solid State ◽  
Spin Exchange ◽  
Magnetic Interaction ◽  
Conjugated Molecules ◽  
Organic Magnets ◽  
Rigid Rod ◽  
Optical And Magnetic Properties ◽  
Solid State Materials

ABSTRACTA series of new stable fiinctionalised aryl ethynyl compounds bearing nitronyl-nitroxy and galvinoxyl radicals were synthesised as potential organic magnets with optical properties. Our goal is to construct biradicals in linear or broken rod molecules with the aim of probing i) the efficiency of the conjugation for the intramolecular spin exchange, and / or ii) the inter-Molecular Magnetic interaction between the neighboring radicals in the solid state Materials.We focused our attention on the preparation of phenoxy, and galvinoxyl biradicals of the conjugated phenyl and thienyl diethynyl Moieties. The synthesis of these new components will be presented. Their optical and magnetic properties will be discussed both in solution and in the solid state.

The electronic, half-metallic, elastic, and magnetic properties of new PtWZ (Z= In, Tl, Sn, and Pb) half-Heusler alloys via GGA and GGA+mBJ methods

2021 ◽  
Author(s):  
Evren Görkem Özdemir ◽  
Semih Doğruer
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Band Gaps ◽  
First Principle ◽  
Full Agreement ◽  
Half Metallic ◽  
First Principle Calculations ◽  
Direct Band ◽  
Curie Temperatures

Abstract The first-principle calculations of PtWZ (Z= In, Tl, Sn, and Pb) half-Heusler alloys were calculated by WIEN2k for GGA and GGA+mBJ methods. First, the ferromagnetic (FM) phases were obtained more energetically stable than non-magnetic (NM) and antiferromagnetic (AFM) phases in each alloy. The Curie temperatures of PtWIn, PtWTl, PtWSn, and PtWPb alloys were obtained as 286.98 K, 467.14 K, 721.98 K, and 1114.31 K, respectively, by utilizing the energy differences of the AFM and FM phases. In each method and alloy used, spin-up electrons showed metallic character. In the GGA method, PtW(In, Tl) alloys have direct band gaps of 0.72044 eV and 0.91488 eV in spin-down electrons, while PtW(Sn, Pb) alloys have indirect band gaps of 1.2558 eV and 1.11892 eV, respectively. In the GGA+mBJ method, the bandgap directions in all compounds remained the same. Here, band gaps in PtW(In, Tl, Sn, and Pb) alloys were obtained as 0.99918 eV, 1.15385 eV, 1.42676 eV, and 1.17497 eV, respectively. While the total magnetic moment values of PtW(In, Tl) half-Heusler alloys were obtained as 1.00 μB/f.u., the total magnetic moments of PtW(Sn, Pb) alloys were obtained as 2.00 μB/f.u. These results are in full agreement with the Slater-Pauling rule. According to elastic calculations, PtWIn, PtWTl, PtWSn, and PtWPb half-Heusler alloys are elastically stable and ductile.

scholarly journals First principles calculations for electronic, optical and magnetic properties of full heusler compounds

2020 ◽  
Keyword(s):  
Magnetic Properties ◽  
Band Gap ◽  
Magnetic Moment ◽  
Magnetic Moments ◽  
Potential Method ◽  
Full Potential ◽  
Metallic Behavior ◽  
Optical Phenomenon ◽  
Minority Spin ◽  
Optical And Magnetic Properties

For the investigation of structural, electronic, optical and magnetic properties of Co2CrZ (Z= In, Sb, Sn) compounds, we have used two different methods. One is based on full potential linearized augmented plane wave (FP-LAPW) method as implemented in WIEN2k and second is pseudo potential method as implemented in Atomistic Tool Kit-Virtual NanoLab (ATK-VNL). These compounds show zero band gap in their majority-spin and minority-spin representing metallic behavior except the compound Co2CrSb, which is showing the band gap 0.54 eV in their minority-spin near the Fermi level and viewing 100% spin polarization; which is implemented in WIEN2k code. Further, the compound Co2CrSb has been found to be perfectly half-metallic ferromagnetic (HMF). However, above mentioned compounds shows zero band gap in ATK-VNL code. Calculations performed using WIEN2k code shows the magnetic moment of these compounds Co2CrZ (Z= In, Sb, Sn) 3.11, 5.00 and 4.00µB respectively. However, the respective magnetic moment of these compounds is found to be 3.14, 5.05 and 4.12µB in ATK-VNL code. Calculated magnetic moments have good agreement with the Slater-Pauling behavior. Optical properties play an important role to understand the nature of material for optical phenomenon and optoelectronics devices. Value of absorption coefficient and optical conductivity of Co2CrSb is greatest than other two compounds. From the absorption and reflection spectra relation, observations indicate that absorption and reflectivity are inversely proportional to each other.

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