ME Output Research Articles

Dielectric and magnetoelectric properties of Li-Mg ferrite: Barium titanate composites

The magnetoelectric composites with composition, (y) Li0.45Mg0.1Fe2.45O4 + (1-y) BaTiO3, where, y = 0.1, 0.3, 0.5, 0.7 and 0.9 are prepared by standard ceramic technique. The X-ray diffraction studies revealed the coexistence of two phases without chemical reaction. The dielectric properties are measured at room temperature in the frequency range from 100 Hz to 5 MHz. Same parameters were also measured by changing the temperature from 25 to 500 °C. The dielectric constant initially decreases rapidly with rise in frequency exhibiting dielectric dispersion at lower frequencies and then remains fairly constant at higher frequencies. The dielectric dispersion observed at low frequencies is of the interfacial polarization type and is attributed to various types of polarizations mechanisms. AC resistivity and dielectric constant show a opposite trend of variation with increase in content of ferrite. The variation of dielectric loss with frequency is in analogous to that of dielectric constant vs. Logf. The dielectric constant vs. temperature curves exhibit peaks around two temperatures i.e. one at around 400 K and other at around 725 K which refers to the ferroelectric and ferromagnetic Curie temperatures. The intensity of the peaks at both the transition temperatures decreases as the fixed applied frequency increases. AC resistivity decreases rapidly with rise in frequency initially, then it do not depend on frequency applied. The rapid fall of resistivity at lower frequency is due to increase in the hopping frequency of the electrons between different ionic sites. The linearity in Logσac vs. Logω2 reveals that the conductivity is due to small polarons. ME output increases with rise in dc magnetic field up to the range 2000–2500 Oe and then decreases for further rise in the field. The peaks observed in the ME output curves is attributed to the enhanced domain wall movements near Curie temperature.

Comparison of Energy Estimates of Mixed Diets Obtained from RIVIGPT and In-vivo Digestibility Trial in NariSuwarna X Kenguri F1 Sheep

To compare the energy estimates of mixed diets obtained from rumen in vitro incubation for gas production (RIVIGP) and digestion trial (DT) in NariSuwarna X Kenguri F1 sheep, twenty four sheep were divided into six groups of five each. Six mixed diets were prepared by using sugarcane trash and concentrate feed mixture in the ratio of T-1 80:20, T-2 70:30, T-3 60:40, T-4 50:50, T-5 40:60 and T-6 30:70. The feeding trial was carried out for the duration of six weeks with an adjustment period of five weeks and collection period of one week. The metabolisable energy (ME, MJ kg-1 DM) content of diets at maintenance level of intake obtained by DT for diets-1, 2, 3, 4, 5 and 6 were 6.7, 6.9, 7.4, 7.2, 7.8 and 9.4 respectively. The corresponding ME values obtained from RIVIGP were 5.3, 5.9, 6.2, 7.5, 8.6 and 9.4 respectively. The difference between the ME obtained from DT (digestion trial) and ME predicted from RIVIGPT was found to be 10.7 per cent. The mean ME output (Maintenance + weight gain) for the diets-1, 2, 3, 4, 5 and 6 were 6.37, 6.34, 7.38, 7.70, 8.06 and 8.27 respectively. The ME intake estimated from ME obtained from DT and RIVIGP for the diets-1, 2, 3, 4, 5 and 6 were 4.91 and 3.79, 5.02 and 4.22, 7.63 and 6.46, 7.74 and 8.13, 8.76 and 9.81, 11.42 and 11.85 respectively. Hence, the observed performance of NariSuwarna x Kenguri F1 sheep expressed in terms of the total ME output was accountable to the extent of 97.0 and 99.6% of ME intake estimates obtained from ME values derived by DT and RIVIGP respectively.

Synthesis and characterization of PZT: CF magnetoelectric composites

ABSTRACTHere, we report the structural, dielectric, ferroelectric, piezoelectric and magnetic properties of ME composites of Lead Zirconate Titanate (PZT) and Cobalt ferrite (CF) with compositional formula (1−x) PbZr0.55Ti0.45O3 + (x) CoFe2O4, (x = 0.00, 0.05, 0.10, 0.15 and 1.00 by weight). The samples were synthesized by conventional solid state reaction. The formation of perovskite tetragonal and spinel structure in the composites are confirmed by X-ray diffraction studies. Microstructural study of all samples was done by SEM analysis and average grain size was also calculated. The dielectric properties of samples were studied as a function of frequency and as a function of temperature (30°C – 500°C) respectively. P-E hysteresis loop at room temperature and piezoelectric coefficient were measured to study the ferroelectric and piezoelectric properties. To confirm the ferromagnetic behavior of the composites M-H hysteresis loop measurement was carried out. The Magnetoelectric voltage coefficient (dE/dH) was measured as a function of applied DC magnetic field. The maximum ME output of 389μV/ (cm.Oe) was observed for the composite with x = 0.15.

Multiferroic properties of lead-free Ni0.5Zn0.5Fe1.9O4−δ−Na0.5Bi0.5TiO3 composites synthesized by spark plasma sintering

Multiferroic composites of x Ni0.5Zn0.5Fe1.9O4−δ−(1−x) Na0.5Bi0.5TiO3 (x NZF−(1−x) NBT, where x=0.05, 0.15 and 0.25 mol fraction) were synthesized by spark plasma sintering (SPS) in conjunction with high-energy ball milling. The presence of NZF and NBT phases in the composites was confirmed by X-ray diffraction. The dielectric constant was studied as a function of frequency (0.5kHz to 1MHz) and temperature (30–500°C). It was found that the 0.25 NZF–0.75 NBT composite possessed the most promising dielectric properties with its dielectric constant being 5–10 times higher than those for the other two composites in the full range of frequency. The magnetic and ferroelectric properties were examined at room temperature and all composite samples exhibited both pronounced ferromagnetic and ferroelectric characteristics. A maximum ME voltage coefficient of ~870μV/cmOe was obtained at the magnetic field of ~1.25kOe for the 0.25 NZF–0.75 NBT composite, which was well comparable with the ME output for the lead-containing NZF–PZT composites.

자기센서용 Ni-PZT-Ni, Co, Fe 적층구조 소자의 ME 특성

Abstract: The magnetoelectric characteristics on layered Ni-PZT-Ni , Co, Fe composites by epoxy bonding for magnetic field sensor were investigated in the low-frequency range. The ME coefficient of Ni-PZT-Ni, Ni-PZT-Co and Ni-PZT-Fe composites reaches a maximum of 200 mV / cm·Oe at H dc =110 Oe , 106 mV/cm·Oe at H dc =90 Oe and 87 mV/cm·Oe at H dc =160 Oe , respectively. A trend of ME charateristics on Ni-PZT-Co , Ni-PZT-Fe composites was similar to that of Ni-PZT-Ni composites . The ME output voltage shows linearly proportional to ac field H ac and is about 0∼150 mV at H ac =0∼7 Oe and f =110 Hz in the typical Ni-PZT-Ni sample. The frequency shift effect due to the load resistance R L shows that the frequency range for magnetic field sensor application can be modulated with appropriate load resistance R L . This sample will allow for a low-magnetic ac field sensor in the low-frequency (near f =110 Hz ). Keywords: Magnetic field sensor, Magnetoelectric effect, Laminate structure, Magnetostriction coefficient

Comparison of Energy Estimates of Mixed Diets Obtained from RIVGPT and in-vivo Digestibility Trials in Lactating Cows

To compare the energy estimates of mixed diets obtained from rumen in vitro incubation for gas production (RIVIGP) and digestion trial (DT) in lactating cows, six cows in mid lactation were divided in to three groups of two each. Three mixed diets were prepared by using finger millet straw (FMS) and concentrate supplements (CS) in the ratio of 41:59 (Diet-1&3) and 43:57 (Diet-2). These diets were tested in three periods in a switch over design. Each period lasted for four weeks with an adjustment period of three weeks and digestion trial for one week. The metabolisable energy (ME, MJ kg-1 DM) content of FMS was 6.6 and CS ranged from 10.5 to 11.4. The ME content of mixed diets at maintenance level of intake obtained by DT for diets-1,2 and 3 were 9.3, 9.7 and 9.5 MJ/kg DM respectively. The corresponding ME values obtained from RIVIGP were 8.9, 9.3 and 9.4 respectively. The mean ME output (Maintenance + 4%FCM yield + weight gain) for the diets-1,2 and 3 were 104.9, 112.3 and 106.9 MJ/d respectively. The ME intake estimated from ME obtained from DT and RIVIGP for the diets-1,2 and 3 were 107.7 and 111.9; 116.6 and 116.9; 103.1 and 110.2 respectively. Hence, the observed performance of growing ram lambs expressed in terms of the total ME output was accountable to the extent of 99.5 and 95.4% of ME intake estimates obtained from ME values derived by DT and RIVIGP respectively.

Dielectric and magnetoelectric properties of Li 0.5Ni 0.75− x/2 Zn x/2 Fe 2O 4 + Ba 0.5Sr 0.5TiO 3 ME composites

The magnetoelectric composites with the composition Y[Li 0.5Ni 0.75− x/2 Zn x/2 Fe 2O 4] + (1 − Y)[Ba 0.5Sr 0.5TiO 3] where x = 0.1, 0.2. 0.3 and Y = 0.1, 0.2, 0.3 were prepared by standard double sintering ceramic technique. The XRD patterns confirmed the coexistence of piezomagnetic and piezoelectric phases. Both dielectric constant ( ɛ′) and loss tangent (tan δ) decrease with increase in frequency exhibiting normal dielectric behaviour. The linearity in the log σ ac vs. log ω 2 plots confirmed the small polaron hopping type of conduction mechanism in the composites studied. Flat curves in the ME output vs. dc magnetic field are obtained which may be due to the presence of strontium in the composites. ME output showed direct relation with the resistivity of the composites.

Effect of load resistance on magnetoelectric properties in FeGa/BaTiO 3/FeGa laminate composites

The electrical resistance load effects on an ME laminated composite of FeGa/BaTiO 3/FeGa are investigated. The results show that (i) The ME voltage coefficient increases and tends to be saturated with the increase in electrical resistance load, (ii) the cutoff frequency and the resonance frequency both shift to the lower frequency side and approach to the values under open-circuit condition with the increase in electrical resistance load, and (iii) the ME output power can be adjustable by changing the attached electrical resistance load to achieve the best active status. The present study provides the basis for the design of ME sensors and their electronic circuits.

Magnetic properties and magnetoelectric (ME) effect in ferroelectric rich Ni 0.2Co 0.8 Fe 2O 4 + PbZr 0.8Ti 0.2O 3 ME composites

Magnetoelectric composites with composition ( x) Ni 0.2Co 0.8Fe 2O 4 (ferrite) + (1 − x)PbZr 0.8Ti 0.2O 3 (ferroelectric) in which x varies as 0.0, 0.15, 0.30, 0.45 and 1.0 mol% have been prepared by double sintering ceramic method. The X-ray diffraction pattern of the composites reveals the formation of spinel structure for the ferrite phase and perovskite structure for the ferroelectric phase without any other phase formation. Scanning electron micrographs (SEM) were taken to understand the microstructure and grain size of the samples. The estimated values of the porosity of the samples lie between 4.5% and 16.2%. Hysteresis measurements were used to determine saturation magnetization ( M s) and magnetic moment ( μ) and the variations of saturation magnetization and magnetic moment were interpreted in terms of the composition of the samples. From AC susceptibility studies the contribution of both single domain (SD) particle of the ferrite phase and mixed (MD + SD) particle of the composites in ME output was discussed. The magnetoelectric voltage coefficient (d E/d H) H was measured as a function of DC magnetic field and the maximum value of ME conversion factor was observed (828 μV cm −1 Oe −1) for the composite with 15% ferrite and 85% ferroelectric phase.

Magnetic properties and magneto electric effect in ferroelectric rich Ni 0.5Zn 0.5Fe 2O 4+BPZT ME composites

Magneto electric composites with composition ( x) Ni 0.5Zn 0.5Fe 2O 4+(1– x) Ba 0.8Pb 0.2Zr 0.8Ti 0.2O 3 (BPZT—barium lead zirconate titanate) in which x varies as 0.0, 0.15, 0.30, 0.45 and 1.0 mol% were prepared by standard double sintering ceramic method. The presence of constituent phases such as ferrite and ferroelectric was confirmed by X-ray diffraction. The structural analyses were carried out by using X-ray diffraction pattern. Scanning electron micrographs (SEM) were taken to understand the microstructure of the samples. The calculated values of the porosity of the samples lie between 4.5% and 16.2%. The hysteresis measurements were made to determine saturation magnetization ( M s), magnetic moment ( μ B) and coercivity ( H c). From the AC susceptibility measurements the contribution of both the single domain (SD) particles of the ferrite phase and mixed domain (SD+MD) particles of the composites in ME output were explained. The static magneto electric voltage coefficients (d E/d H) H were measured as a function of intensity of magnetic field and the maximum ME coefficient were observed for the composites with 30% of ferrite+70% of ferroelectric phase.

Assessment of rumen in vitro incubation (gas production) technique and chemical analyses by detergent system to predict metabolisable energy content in mixed diets of lactating cows

A study was conducted to assess the potential of rumen in vitro incubation for gas production (RIVIGP) and summative equations of detergent system (SEDS) to obtain estimates of energy values in mixed diets. The feeding experiments included digestion trials (DT) to obtain energy values and feeding trials (FT) to assess the potential of energy values obtained by DT, RIVIGP and SEDS to account for the observed performance in lactating cows. Six feeding experiments were conducted using six diets. Each experiment included four cows except the fifth, which included three cows. The FT lasted for 9–11 weeks and the DT for seven days during the FT. The diet was made from either finger millet straw (FMS) or chaffy-paddy hay (CPH) and compounded feed mixture (CFM). The metabolisable energy (ME, MJ kg −1 DM) content of total diet at maintenance level of intake obtained by DT for diets 1–6 were 11.0, 9.2, 10.5, 10.1, 8.8 and 7.6 respectively. The corresponding estimates obtained from RIVIGP and SEDS were 10.2 and 10.2, 9.1 and 9.2, 9.5 and 10.7, 9.4 and 10.5, 8.3 and 7.1, 6.6 and 6.9 respectively. The relationship of ME (DT) ( y) with ME (RIVIGP) and ME (SEDS) were y=1.11+.95 x ( r 0.96, P <0.01) and y=3.5+0.66 x ( r 0.91, P<0.01) respectively. The mean ME output (Maintenance+4% FCM yield+gain) for the six experiments was 103.5±2.9. The ME intake estimated from ME obtained from DT, RIVIGP and SEDS were 112.7±5.3, 106.4±4.3 and 111.1±6.7 respectively. Thus the observed performance of lactating cows expressed in terms of the total ME output was accountable to the extent of 92, 97 and 93% of ME intake estimates obtained from ME values derived by DT, RIVIGP and SEDS respectively, indicating the potentials of ME values obtained from RIVIGP and SEDS in diet formulation for lactating cows.