High Damping in Ferroelectric and Ferrimagnetic Ceramics

High damping materials exhibiting a loss factor higher than 10-2 are generally considered as polymer or metallic materials. But, it will be interesting to consider ferroelectric or ferrimagnetic ceramics, in which internal friction can be due to the motion of ferroelectric or magnetic domains. High level of internal friction can be obtained in these ceramics in a given temperature range. In the case of ferroelectric ceramics, hard ferroelectrics, such as BaTiO3 or PZT, can show some relaxation peaks below the Curie temperature due the motion of domain walls and the interaction between the domain walls and the oxygen vacancies or cationic vacancies. In the case of ferrimagnetic ceramics, some anelastic manifestations due to the ferrimagnetic domain walls appear below the Curie Temperature TC. These peaks are linked to the interaction of domain walls with cation vacancies or cation interstitials or the lattice. Above the Curie temperature, a relaxation mechanism due to the exchange of cations Mn3+ and their vacancies on octahedral sites should occur.

Download Full-text

Mapping of Magnetic Domains by MFM in Ni2MnGa

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.52.115 ◽

2008 ◽

Vol 52 ◽

pp. 115-119 ◽

Cited By ~ 2

Author(s):

Deepti Jain ◽

Soma Banik ◽

L.S. Sharath Chandra ◽

S.R. Barman ◽

R. Nath ◽

...

Keyword(s):

Domain Walls ◽

Alloy System ◽

Optical Microscope ◽

Magnetic Domains ◽

Local Magnetization ◽

Force Microscopy ◽

Domain Structures ◽

Two Samples ◽

Ferromagnetic Shape Memory ◽

Curie Temperature Tc

Influence of structural transition in the evolution of the magnetic domains in the ferromagnetic shape memory alloy system Ni2+xMn1-xGa is reported here using Magnetic Force Microscopy (MFM) studies. Studies reported are with two samples with their martensite transition temperature TM less than and greater than the Curie temperature Tc. Present results show an evolution of MFM across the Tc with a clear twin domains and sub domain structures inside the twins. The higher spatial resolution of MFM (~50nm) as compared to optical microscope (400nm) is useful in probing the domain walls. Force derivative of the MFM signal that may be used as an order parameter seems to scale the onset of magnetic order in the system. One can clearly see the vanishing of the MFM patterns for T>Tc. Results are discussed in the light of models available for tip-sample interactions that track the local magnetization.

Download Full-text

A Simple Method for Identification of the Alloy’s Non-Crystalline Structure

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.567.3 ◽

2013 ◽

Vol 567 ◽

pp. 3-7

Author(s):

Hua Xing Xiao

Keyword(s):

Amorphous Alloy ◽

Curie Temperature ◽

Crystalline Structure ◽

Crystallization Temperature ◽

Heating Temperature ◽

High Curie Temperature ◽

Simple Method ◽

Before And After ◽

High Level ◽

Curie Temperature Tc

In the thermomagnetism analysis, the ferromagnetic amorphous alloy near or after the Curie temperature within a certain scope was in the paramagnetic condition with low magnetization. When the heating temperature achieved the crystallization temperature of the amorphous alloy, the magnetization increased significantly due to the crystallization of the alloy. As the obvious crystallization of the amorphous alloy, the crystallization phase with a high Curie temperature (Tc) formed and the ferromagnetism of the alloy would not be fully transferred to paramagnetism. The magnetization of the alloy would maintain at a stable high level before it had been fully crystallized. Therefore, the structure of the ferromagnetic amorphous alloy can be identified accurately by the obvious difference between the thermomagnetism curves before and after crystallization.

Download Full-text

Lorentz microscopy study of magnetic domain walls in Fe-Cr-Co alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109458 ◽

1978 ◽

Vol 36 (1) ◽

pp. 462-463

Author(s):

Yalcin Belli

Keyword(s):

Domain Walls ◽

Magnetic Domain ◽

Microscopy Study ◽

Ferromagnetic Phase ◽

Stable Phase ◽

Magnetic Domains ◽

Lorentz Microscopy ◽

Magnetic Hardening ◽

Electron Microscopes ◽

Co Alloys

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.

Download Full-text

Calcium Bismuth Titanate with High Curie Temperature (Tc) for High-Temperature Sensor Applications

Journal of Electronic Materials ◽

10.1007/s11664-021-09029-w ◽

2021 ◽

Author(s):

P. Sivagnanapalani ◽

Naveed Iqbal Ansari ◽

P. K. Panda

Keyword(s):

High Temperature ◽

Curie Temperature ◽

Temperature Sensor ◽

Bismuth Titanate ◽

High Curie Temperature ◽

Sensor Applications ◽

High Temperature Sensor ◽

Curie Temperature Tc

Download Full-text

Damping Performance of Material Candidates for Service at 350K

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.315.43 ◽

2021 ◽

Vol 315 ◽

pp. 43-49

Author(s):

Si Bin Zhang ◽

Ze Chao Jiang ◽

Qing Chao Tian

Keyword(s):

Internal Friction ◽

Single Phase ◽

Vibration Reduction ◽

Physical Parameters ◽

Heating Rates ◽

Friction Mechanism ◽

Obvious Effect ◽

Negative Linear Correlation ◽

Resonance Frequencies ◽

Damping Materials

Vibration systems require the damping materials operating at high service temperature. In this paper, damping performance of HT100, M2052 and S316L at 350K were evaluated by applying different frequencies, strain amplitudes and heating rates. It is found that the internal friction dependence of frequency of HT100, M2052 and S316L all show a characteristic of Check function, and the resonance frequency has a negative linear correlation with the material physical parameters. The strain amplitude as well as heating rate has no obvious effect on the resonance frequencies of the materials, but significantly enhance the internal friction of the interface damping alloys such as M2052 and HT100, but small on single-phase alloys such as S316L. The internal friction mechanism for HT100 and M2052 are of static hysteresis at 350K, and HT100 and M2052 are applicable candidates for working at temperatures around 350K from the viewpoint of vibration reduction.

Download Full-text

Piezoelectric Properties of SrBi4Ti4O15 Ferroelectric Ceramics

Journal of Materials Research ◽

10.1557/jmr.2002.0205 ◽

2002 ◽

Vol 17 (6) ◽

pp. 1376-1384 ◽

Cited By ~ 30

Author(s):

Marlyse Demartin Maeder ◽

Dragan Damjanovic ◽

Cyril Voisard ◽

Nava Setter

Keyword(s):

Piezoelectric Coefficient ◽

Domain Walls ◽

High Pressures ◽

Elevated Temperatures ◽

Piezoelectric Properties ◽

Ferroelectric Ceramics ◽

Piezoelectric Response ◽

Low Frequencies ◽

Sintering Conditions ◽

Weak Fields

The dynamic piezoelectric response of SrBi4Ti4O15 ceramics with Aurivillius structure was investigated at high alternating stress, low frequencies (0.01 to 100 Hz), and temperatures from 20 to 200 °C. The piezoelectric nonlinearity, observed only at high pressures (>10 MPa) and elevated temperatures (>150 °C), is interpreted in terms of contributions from non-180° domain walls. At weak fields, the frequency dependence of the longitudinal piezoelectric coefficient was explained in terms of Maxwell–Wagner piezoelectric relaxation. The Maxwell–Wagner units are identified as colonies that consist of highly anisotropic grains which sinter together, and whose distribution in the ceramic is strongly dependent on sintering conditions.

Download Full-text