Penelitian ini membahas kinetika pertumbuhan kristal dan karakterisasimaterial penyerap gelombang mikro berbahan dasar LSMO di substitusi Fe-Tidengan formula La0.5Sr0.5Mn0.8Fe0.1Ti0.1O3. Preparasi material menggunakanmetode paduan mekanik selama 10 jam, kemudian diberikan variasi waktu 0, 1, 5dan 24 jam pada temperatur 1000 C, 1100 C dan 1300 C. Pengujian XRDsebelum proses sintering dan sesudah sintering yang menunjukan hasil bahwasintesa bahan atau paduan La0.5Sr0.5Mn0.8Fe0.1Ti0.1O3 memiliki fasa tunggal (singlephase) dengan struktur kristal orthorombik dengan parameter kisi a=7.7 Å ; b=5.5Å ; c=5.4 Å. Berdasarkan hasil pengukuran ukuran kristal rata-rata melaluimetode Debye-Scherrer, kinetika pertumbuhan kristal rata-rata mengikutipersamaan Avrami dengan nilai energi aktivasi sebesar Q=21.29 kJ/mol.K.Karakteristik nilai serapan gelombang mikro pada frekuensi 8?15 GHz dianalisamenggunakan Vector Network Analyzer (VNA). Karakterisasi kurva reflektansiloss sampel material T1300-24jam memberikan nilai intensitas yang palingoptimal yaitu sebesar -3.58 dB atau 34% frekuensi serapan pada frekuensi optimal12.5 GHz, dan lebar pita penyerapan sebesar 3 GHz.
Abstract
The kinetics of crystallite growth and microwave characteristics for Fe-Tisubstituted LSMO with La0.5Sr0.5Mn0.8Fe0.1 Ti0.1O3 composition was investigated.Material preparation was carried out by means of mechanical alloying process for10 hours milling times. The powders which prepared from mechanically milledmaterial were sintered at temperatures 1000 C, 1100 C dan 1300 C respectivelyfor 0, 1, 5 and 24 hours time sintering time. The XRD traces for sintered materialsconfirmed that the La0.5Sr0.5Mn0.8Fe0.1 Ti0.1O3 is a single phase material with aorthomobic crystal structure a=7.7 Å ; b=5.5 Å ; c=5.4 Å. Refering to meancrystallite size evaluation which employing Debye Scherrer method. It was foundthat the kinetics of mean crystallite growth followed the Avrami equation with anactivation energy for crystallite growth Q=21.29 kJ/mol.K. In addition tocrystallite growth kinetics the absorbtion characteristics of material was evaluatedby a Vector Network Analyzer (VNA) in the electromagnetic frequency range 8-15GHz. The best absorbtion characteristics was found in the sample code T1300-24h. This follows that the reflection loss of -3.58 dB or 34% was absorb occurredat frequency 12.5 GHz was the bandwith 3GHz. |
