Sains Malaysiana 46(6)(2017): 967–973

http://dx.doi.org/10.17576/jsm-2017-4606-16

Structural, Magnetic and Electrical Properties of Barium Titanate and Magnesium Ferrite Composites

(Struktur, Sifat Magnet dan Elektrik Komposit Barium Titanat dan Ferit Magnesium)

MOHAMAD FAHMI AMIN BIN ZOLKEPLI & ZALITA ZAINUDDIN*

Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Received: 11 April 2016/Accepted: 25 November 2016

ABSTRACT

Structural, magnetic and electrical characteristics of multiferroics (1-x)BaTiO₃-xMgFe₂O₄ composites with weight fractions of x = 0.3, 0.5 and 0.7 are reported. MgFe₂O₄ powders were prepared using sol-gel auto combustion technique. It was combined with commercial BaTiO₃ to form composites by using wet milling solid state reaction technique. Formation of tetragonal perovskite for the ferroelectric BaTiO₃ and cubic spinel for the ferrimagnetic MgFe₂O₄ phases, were identified from the XRD pattern. The average grain size for each composite was about 0.5 μm. The M-H loop showed soft ferrimagnetic properties due to the presence of MgFe2O4 in the composites. The increment of the MgFe₂O₄ weight fraction increased the saturation magnetization and slightly changed the coercive field. The complex impedance plot can be represented by a parallel R and C circuit. Composite sample with x = 0.5 has the highest resistance with lowest capacitance and dielectric constant value at room temperature. The dielectric constant showed a very strong dispersion at low frequencies, due to the Maxwell-Wagner mechanism and a slight dispersion at higher frequencies. Based on the results obtained, all of the composite samples exhibited high dielectric constant and tangent loss at the low frequency range.

Keyword: Ceramic; dielectric; ferrimagnet; ferroelectric

ABSTRAK

Struktur, sifat magnet dan elektrik komposit multiferoik (1-x)BaTiO₃-xMgFe₂O₄ dengan pecahan berat, x = 0.3, 0.5 dan 0.7 dilaporkan. Serbuk MgFe₂O₄ telah disediakan menggunakan teknik sol-gel pembakaran auto. Ia digabungkan bersama BaTiO₃ komersil untuk membentuk komposit dengan menggunakan teknik tindak balas keadaan pepejal pengisaran basah. Pembentukan fasa perovskit tetragon bagi feroelektrik BaTiO₃ dan fasa kubus spinel bagi ferimagnet MgFe₂O₄, dikenal pasti daripada corak XRD. Purata saiz butiran setiap komposit ialah 0.5 μm. Lengkung M-H menunjukkan sifat-sifat ferimagnet lembut disebabkan oleh kehadiran MgFe₂O₄ di dalam komposit. Kenaikan pecahan berat MgFe₂O₄ meningkatkan pemagnetan tepu dan mengubah sedikit medan paksa. Plot impedans kompleks boleh diwakili oleh litar selari R dan C. Sampel komposit x = 0.5 mempunyai rintangan tertinggi serta nilai kapasitans dan pemalar dielektrik terendah pada suhu bilik. Pemalar dielektrik menunjukkan penyerakan yang tinggi pada frekuensi rendah disebabkan mekanisme Maxwell-Wagner dan sedikit penyerakan pada frekuensi lebih tinggi. Berdasarkan hasil yang diperoleh, kesemua sampel komposit memaparkan pemalar dielektrik dan kehilangan tangen yang tinggi pada julat frekuensi rendah.

Kata kunci: Dielektrik; ferimagnet; feroelektrik; seramik

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*Pengarang untuk surat-menyurat; email: zazai@ukm.edu.my