MAGNETIC BEHAVIOR OF IRON IONS IN THE P2O5·CaO GLASS MATRIX

2003 ◽  
Vol 17 (24) ◽  
pp. 1271-1275 ◽  
Author(s):  
I. ARDELEAN ◽  
C. ANDRONACHE ◽  
P. PǍŞCUŢǍ
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Magnetic Moment ◽  
Glass Matrix ◽  
Magnetic Behavior ◽  
Iron Ions ◽  
Ion Content ◽  
Dipole Interactions ◽  
Valence States ◽  
Temperature Susceptibility

The temperature dependence of the magnetic susceptibility of x Fe 2 O 3·(100-x)-[ P 2 O 5· CaO ] glasses with 0<x≤50 mol % have been investigated. These data revealed that the valence states and the distribution of iron ions in the glass matrix depend on the Fe 2 O 3 content. For the glasses with x≤1 mol % only Fe 3+ ions are evidenced. In the case of the glasses with 3≤x≤35 mol % both Fe 3+ and Fe 2 ions co-exist in the P 2 O 5· CaO glass matrix, the Fe 2+ ion content is higher than that of the Fe 3+ ions for glasses with x≥10 mol %. For the glasses with x>35 mol %, the evaluated values of the μ eff indicate either the presence of Fe + ions or the coordination influence on the magnetic moment of iron ions, but the presence of small quantities of the antiferromagnetic or ferrimagnetic interactions between iron ions in studied temperature range cannot be excluded. The high temperature susceptibility results indicate that the iron ions are isolated or participate in dipole-dipole interactions for glasses with x≤35 mol % and are antiferromagnetically coupled for higher contents of Fe 2 O 3.

EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF IRON IONS IN THE 3B2O3·KF GLASS MATRIX

2004 ◽  
Vol 18 (10n11) ◽  
pp. 1525-1535 ◽  
Author(s):  
I. ARDELEAN ◽  
P. PASCUTA
Keyword(s):  
Magnetic Susceptibility ◽  
Iron Content ◽  
Glass Matrix ◽  
Structural Changes ◽  
Magnetic Measurement ◽  
Measurement Data ◽  
Ionic Species ◽  
Iron Ions ◽  
Simultaneous Presence ◽  
Valence States

Glasses of the x Fe 2 O 3·(100–x)[3 B 2 O 3· KF ] system, with 0<x≤35 mol %, were investigated by means of EPR and magnetic susceptibility measurements. When increasing the iron content the EPR absorption spectra undergo modification reflecting structural changes of the glass matrix and also the distribution and valence states of iron ions. The magnetic measurement data pointed out the character of interaction involving iron ions as depending on concentration and the simultaneous presence of both Fe 3+ and Fe 2+ ionic species.

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%.

EPR and Magnetic Susceptibility Studies of Iron Ions in 3B2O3·CaCl2 Glass Matrix

2003 ◽  
Vol 17 (21) ◽  
pp. 3889-3897 ◽  
Author(s):  
I. Ardelean ◽  
P. Păşcuţă
Keyword(s):  
Magnetic Susceptibility ◽  
Glass Matrix ◽  
Iron Ions ◽  
Structural Units ◽  
Valence States

Glass matrix 3B 2 O 3· CaCl 2 doped with iron ions up to 50 mol% were obtained and investigated by means of EPR and magnetic susceptibility. Information concerning the structural units involving iron ions, valence states and the type of the interactions between these ions were discussed.

MAGNETIC BEHAVIOR OF SAMARIUM IONS IN 2B2O3 · PbO GLASS MATRIX

2002 ◽  
Vol 16 (20) ◽  
pp. 757-760
Author(s):  
I. ARDELEAN
Keyword(s):  
Magnetic Susceptibility ◽  
Glass Matrix ◽  
Magnetic Behavior ◽  
Van Vleck

Magnetic susceptibility measurements were performed on x Sm 2 O 3 · (100 - x)[ 2B 2 O 3 · PbO ] glasses with x ≤ 40 mol %. These data were analyzed using the Van Vleck model for magnetic behavior of free Sm 3+ ions.

IRON OXIDATION STATES AND DISTRIBUTION IN THE 4Bi2O3· PbO GLASS MATRIX

2002 ◽  
Vol 16 (01n02) ◽  
pp. 41-46 ◽  
Author(s):  
V. SIMON ◽  
R. POP ◽  
M. NEUMANN ◽  
S. G. CHIUZBAIAN ◽  
M. COLDEA ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Valence State ◽  
Glass Matrix ◽  
Iron Oxidation ◽  
Oxidation States ◽  
Iron Ions ◽  
Metallic Elements ◽  
Iron Oxidation States

Magnetic susceptibility and XPS results on x Fe 2O3 · (100-x) [4 Bi 2O3 · PbO] where 0<x ≤20 samples are presented in order to point out the oxidation states and the distribution of iron ions in the lead-bismuthate matrix. The valence state of iron ions changes from Fe3+ to Fe2+ as the Fe2O3 content increases from 1 to 20 mol%. The XPS data indicate the migration of metallic elements in the inner part of the bulk investigated samples.

Structural and Magnetic Investigations of Fe2O3-B2O3-CaF2 Glass System

2003 ◽  
Vol 17 (13) ◽  
pp. 2633-2641 ◽  
Author(s):  
I. Ardelean ◽  
P. Pǎşcuţǎ ◽  
V. Ioncu
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Mixed Oxide ◽  
Glass System ◽  
Iron Ions ◽  
Structural Units ◽  
Valence States ◽  
Structural And Magnetic Properties

The structural and magnetic properties of a mixed oxide-fluoride vitreous matrix 3B 2 O 3· CaF 2 containing iron ions were investigated. Information concerning the structural units involving iron ions, their valence states and the type of interactions between them were obtained using EPR and magnetic susceptibility measurements.

STRUCTURAL AND MAGNETIC BEHAVIOR OF STRONTIUM-BORATE GLASSES DOPED WITH IRON IONS

2008 ◽  
Vol 22 (05) ◽  
pp. 359-368 ◽  
Author(s):  
I. ARDELEAN ◽  
R. LUNGU ◽  
P. PASCUTA
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Behavior ◽  
Relative Content ◽  
Borate Glasses ◽  
Iron Ions ◽  
Paramagnetic Resonance ◽  
Magnetic Susceptibility Data ◽  
Susceptibility Data ◽  
Strontium Borate ◽  
Electron Paramagnetic

Glasses of the x Fe 2 O 3 · (100 - x)[2 B 2 O 3 · SrO ] system (0 ≤ x ≤ 40 mol% ) were prepared and studied by electron paramagnetic resonance (EPR) and magnetic susceptibility measurements. EPR investigations indicated the compositional domains favorable to the presence of isolated iron ions or to those magnetically clustered. The magnetic susceptibility data evidenced the presence of both Fe 3+ and Fe 2+ ions, with their relative content depending on the Fe 2 O 3 concentration. Dipolar and superexchange interactions involving iron ions were revealed depending on the iron content of the sample.

EPR and magnetic susceptibility studies of iron ions in 70TeO2·25B2O3·5PbO glass matrix

1997 ◽  
Vol 102 (4) ◽  
pp. 341-346 ◽  
Author(s):  
I. Ardelean ◽  
M. Peteanu ◽  
S. Filip ◽  
V. Simon ◽  
G. Györffy
Keyword(s):  
Magnetic Susceptibility ◽  
Glass Matrix ◽  
Iron Ions

MAGNETIC BEHAVIOR OF Al2GdNi COMPOUND

2006 ◽  
Vol 20 (08) ◽  
pp. 401-408 ◽  
Author(s):  
M. COLDEA ◽  
V. POP ◽  
L. G. PASCUT ◽  
D. TODORAN ◽  
R. PACURARIU
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Exchange Interaction ◽  
Magnetic Moment ◽  
Magnetic Measurements ◽  
Spontaneous Magnetization ◽  
Magnetic Behavior ◽  
Spin Fluctuations ◽  
Local Exchange

The magnetic properties of Al 2 GdNi compound have been investigated using magnetic measurements in the temperature range 4.2–300 K and with magnetic fields of up to 9 T. Al 2 GdNi orders ferromagnetically at Tc = 36.7 K with a magnetic moment of 7.25 μB/ f.u. , obtained from the spontaneous magnetization extrapolated to 0 K. The magnetic susceptibility obeys the Curie–Weiss law with μ eff = 8.6 μB/ f.u. and θp = 26.8 K . The results are discussed in terms of the Ruderman–Kittel–Kasuya–Yosida theory, the polarization of 5d electrons by the local exchange interaction 4f-5d and the spin fluctuations on Ni sites.

MAGNETIC PROPERTIES OF Pr6O11-B2O3-CdO GLASSES

2002 ◽  
Vol 16 (08) ◽  
pp. 285-289 ◽  
Author(s):  
I. ARDELEAN
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Behavior ◽  
Valence States ◽  
Praseodymium Ions

Magnetic susceptibility measurements have been performed on x Pr 6 O 11 · (100 - x)- [2 B 2 O 3 · CdO ] glasses with 0 < x ≤ 30 mol%. The data give evidence that for x > 1 mol% the praseodymium ions in these glasses are in Pr3+ and Pr4+ valence states, which explains their magnetic behavior.

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