Ac Susceptibility Studies of New and Familiar Magnetic Molecular Solids

1997 ◽  
Vol 488 ◽  
Author(s):  
Roger D. Sommer ◽  
Brenda J. Korte ◽  
Scott P. Sellers ◽  
Gordon T. Yee
Keyword(s):  
Applied Field ◽  
Magnetic State ◽  
Ac Susceptibility ◽  
Strong Dependence ◽  
Single Frequency ◽  
Molecular Solids ◽  
Standard Practice ◽  
Susceptibility Data ◽  
Ac Susceptometry ◽  
Molecular Solid

Abstractac Susceptometry has been used to study a number of magnetic molecular solids including a new compound, Mn(II) octaethyltetraazaporphyrin, α-MnOETAP, and decamethylmanganocenium tetracyanoethenide, Mn(Cp*)2•TCNE, a previously reported molecule-based ferromagnet. Both of these compounds exhibit signatures of ferromagnetism including significant hysteresis below 2 K and rapidly increasing χT (where χ is the molar susceptibility) with decreasing temperature. However, their ac susceptibility data show relatively strong dependence of χ′ and χ″ on the frequency of the applied field, indicating a spinglass state. Other molecular ferromagnetic solids examined show much less sensitivity. These studies indicate that the standard practice of characterization by dc and ac susceptometry at a single frequency are clearly insufficient for identifying the magnetic state of a molecular solid.

INTERGRANULAR PROPERTIES OF (Y1-x-yZrxCay)Ba2Cu3O7-δ COMPOUNDS

1999 ◽  
Vol 13 (13) ◽  
pp. 1645-1654 ◽  
Author(s):  
I. GR. DEAC ◽  
E. BURZO ◽  
A. V. POP ◽  
V. POP ◽  
R. TETEAN ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ac Susceptibility ◽  
Temperature Dependent ◽  
Susceptibility Data ◽  
Dc Magnetic Field ◽  
Complex Susceptibility ◽  
Granular Superconductors ◽  
Intergranular Critical Current Density

The intergranular properties of ( Y 1-x-y Zr x Ca y) Ba 2 Cu 3 O 7-δ ceramics were studies by using temperature-dependent ac susceptibility measurements at zero dc magnetic field. The intergranular critical current density was determined from ac susceptibility data by varying the field amplitude H ac . From the imaginary part of the complex susceptibility, χ″(T), we have determined the temperature dependence of the critical current density by using the Bean's model. The ac field dependencies of the intergrain χ″-peak temperatures T p are linear and agree with Müller critical state model. The results were analyzed in terms of superconductor-insulator-superconductor (SIS)-and superconductor-normal-superconductor (SNS)-type models for granular superconductors.

scholarly journals Field Induced Slow Magnetic Relaxation in a Non Kramers Tb(III) Based Single Chain Magnet

2018 ◽  
Vol 4 (4) ◽  
pp. 59 ◽  
Author(s):  
Ajit Kumar Kharwar ◽  
Arpan Mondal ◽  
Sanjit Konar
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Energy State ◽  
Ac Susceptibility ◽  
Fluorescence Emission ◽  
Green Light ◽  
Single Chain ◽  
Ferromagnetic Interaction ◽  
Susceptibility Data ◽  
Nitrobenzoic Acid

Herein, we report a novel Tb(III) single chain magnet with the chemical formulae [Tb(μ-OH2)(phen)(μ-OH)(nb)2]n by using 4-nitrobenzoic acid (Hnb) and 1,10-phenanthroline (phen) as ligand system. The single-crystal X-ray diffraction reveals that 4-nitrobenzoic acid acts as a monodentate ligand, water and hydroxyl ions are the bridging ligand and the phen serves as a bidentate chelating ligand. The static magnetic susceptibility measurement (from 2 K to 300 K) shows ferromagnetic interaction at very low temperature (below 6 K). The alternating current (AC) susceptibility data of the complex show temperature and frequency dependence under an applied 2000 Oe DC (direct current) field. The phen moiety behaves as an antenna and enables the complex to show the green light fluorescence emission by absorption-energy transfer-emission mechanism. To calculate the exchange interaction, broken symmetry density functional theory (BS-DFT) calculations have been performed on a model compound which also reveals weak ferromagnetic interaction. Ab initio calculations reveals the anisotropic nature (gz = 15.8, gy, gy = 0) of the metal centre and the quasi doublet nature of ground state with small energy gap and that is well separated from the next excited energy state.

THE EFFECT OF PARTIAL ATOMIC SUBSTITUTION ON ELECTRIC AND MAGNETIC PROPERTIES OF (Bi,Pb):2223 SINTERED SUPERCONDUCTORS

2003 ◽  
Vol 17 (26) ◽  
pp. 4675-4681 ◽  
Author(s):  
A. V. POP ◽  
M. POP ◽  
I. I. GERU
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Electrical Resistance ◽  
Ac Susceptibility ◽  
Partial Substitution ◽  
Superconducting Transition ◽  
Ac Magnetic Susceptibility ◽  
Atomic Concentration ◽  
Susceptibility Data ◽  
Atomic Substitution

The effect of partial substitution of Ca by x = 0.02 La on the electrical and magnetically properties of two (Bi,Pb):2223 superconductor ceramic S1 and S2 (with different Pb and Sr atomic concentration) were investigated by using electrical resistance and AC magnetic susceptibility measurements. The parameters from linear resistivity data in the normal state and superconducting transition are sensitive to the compounds stoechiomerty. The intergrain critical current density JcJ(T) dependence near Tc obtained from immaginary AC susceptibility data agrees with the assumption of SNS intergrain junctions.

Nanophase Separation and Magnetic Spin Glass in Nd2/3Ca1/3MnO3

2012 ◽  
Vol 190 ◽  
pp. 675-678
Author(s):  
Marcela Kajňaková ◽  
Alexander Feher ◽  
Elena Fertman ◽  
Vladimir Desnenko ◽  
Anatoly Beznosov ◽  
...  
Keyword(s):  
Frequency Dependence ◽  
Spin Glass ◽  
Colossal Magnetoresistance ◽  
Magnetic State ◽  
Ac Susceptibility ◽  
Relaxation Times ◽  
Three Dimensional ◽  
Dynamical Scaling ◽  
Glass State ◽  
Competing Interaction

A study of the low temperature magnetic state of polycrystalline colossal magnetoresistance perovskite Nd2/3Ca1/3MnO3 has been carried out. The data obtained, such as strongly divergent ZFC and FC static magnetizations and frequency dependent ac susceptibility, are evident of the glassy magnetic state of the system. Well defined maxima Tmax in the in-phase linear ac susceptibility χ curves were observed, indicating a spin-glass transition. Clear frequency dependence of the cusp temperature Tmax was found. The frequency dependence of Tmax was successfully analyzed by the dynamical scaling theory of a three-dimensional spin glass. Slow relaxation process and variety of relaxation times found imply a cluster glass magnetic state of the compound at low temperatures rather than a canonical spin glass state. The cluster glass state, accompanied by the multiple magnetic transitions of Nd2/3Ca1/3MnO3, might exist due to the competing interaction between the FM clusters and the AFM matrix induced by the complex nanophase segregated state of the compound.

AC susceptibility data on Dy2O3 seeded randomly oriented Dy-123 mono domains melt-textured superconductor

1998 ◽  
Vol 53 (1-2) ◽  
pp. 198-202 ◽  
Author(s):  
Ph. Vanderbemden ◽  
H. Bougrine ◽  
M. Ausloos ◽  
F. Auguste ◽  
R. Cloots
Keyword(s):  
Ac Susceptibility ◽  
Susceptibility Data

THE INFLUENCE OF ATOMIC SUBSTITUTIONS AND SINTERING TEMPERATURE ON ELECTRICAL RESISTANCE AND IRREVERSIBILITY LINE OF (Bi,Pb):2223 BULK SUPERCONDUCTORS

2004 ◽  
Vol 18 (15) ◽  
pp. 2169-2176 ◽  
Author(s):  
A. V. POP ◽  
G. ILONCA ◽  
M. POP ◽  
D. MARCONI
Keyword(s):  
Electrical Resistance ◽  
Sintering Temperature ◽  
Ac Susceptibility ◽  
Nonlinear Dependence ◽  
Thermal Treatments ◽  
Susceptibility Data ◽  
Bulk Superconductors ◽  
Ceramic Samples ◽  
Josephson Medium ◽  
Superconducting Ceramic

Superconducting ceramic samples ( Bi , Pb ):2223 (sample V) and ( Bi )( Pb ),( Sr , Ba ):2223 (samples S1 and S2) were investigated by electrical resistance and AC magnetic susceptibility measurements. The intergrain critical current density J cJ (T) dependence near T c obtained from imaginary AC susceptibility data agrees with the assumption of SNS intergrain junctions, and are sensitive to the compounds stoichiomerty and thermal treatments. The crossover from linear to nonlinear dependence of T p (H AC ) of irreversible line (IL) observed in all samples, was discussed based on the modification of Josephson medium in the Muller model.

scholarly journals Cobalt(II) Complexes Based on Benzylmalonate Anions Exhibiting Field-Induced Single-Ion Magnet Slow Relaxation Behavior

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1130
Author(s):  
Ekaterina Zorina-Tikhonova ◽  
Anna Matyukhina ◽  
Ivan Skabitskiy ◽  
Maksim Shmelev ◽  
Denis Korchagin ◽  
...  
Keyword(s):  
Molecular Complex ◽  
Magnetic Relaxation ◽  
Ac Susceptibility ◽  
Relaxation Behavior ◽  
Magnetic Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Susceptibility Data ◽  
Molecular And Crystal Structures ◽  
2D Polymer

The reaction of (NBu4)2Bzmal (where Bzmal2− is benzylmalonate dianion) with Co(OAc)2∙4H2O gives the [Co(Bzmal)(EtOH)(H2O)]n 2D-polymer (1). The addition of 2,2′-bipyridine (bpy) to the starting system results in the [Co(Bzmal)(bpy)2]·H2O·EtOH molecular complex (2). Their molecular and crystal structures were analyzed by single-crystal X-ray crystallography. An analysis of the static magnetic data supported by the SA-CASSCF/NEVPT2 calculations revealed the presence of easy-plane magnetic anisotropy in both complexes. The AC susceptibility data confirm that both complexes show a slow field-induced (HDC = 1000 Oe) magnetic relaxation behavior.

Transport, AC-Susceptibility and PQR Measurements of Strongly Electron Correlated Compound YbInCu4 at High Pressures

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3661-3663 ◽  
Author(s):  
S. Wada ◽  
T. Mito ◽  
T. Koyama ◽  
T. C. Kobayashi ◽  
T. Muramatsu ◽  
...  
Keyword(s):  
High Pressures ◽  
Ambient Pressure ◽  
Ac Susceptibility ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Kondo Temperature ◽  
Quadrupole Frequency ◽  
Susceptibility Data ◽  
Spin Lattice

We have investigated physical properties of the valence fluctuating compound YbInCu 4 at high pressures and low temperatures. The first-order valence transition temperature TV ~ 42 K at ambient pressure is completely suppressed for pressures above 2.49 GPa. Present electrical resistivity data in the pressure-stabilized high-temperature (HT) phase exhibit successive shoulders at around 20 and 2.4 K. The former can reasonably be compared with the Kondo temperature TK ~ 25 K estimated from the static-susceptibility data at ambient pressure. For pressures above 2.27 GPa, the ac-susceptibility showed a clear peak at 2.4 K, which can be explained as the onset of a long-range ferromagnetic ordering. 63 Cu pure-quadrupole-resonance in the HT phase showed that the value of spin-lattice relaxation time T1 and the almost T-independent behavior are hardly affected with pressure up to 1.3 GPa, in contrast to the large increase in quadrupole frequency.

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