Magnetic Properties of Polycrystalline Bismuth Ferrite Thin Films Grown by Atomic Layer Deposition

Abstract

The atomic layer deposition (ALD) method was applied to grow thin polycrystalline BiFeO3 (BFO) films on Pt/SiO2/Si substrates. The 50 nm thick films were found to exhibit high resistivity, good morphological integrity, and homogeneity achieved by the applied ALD technique. Magnetic characterization revealed saturated magnetization of 25 emu/cm(3) with temperature-dependent coercivity varying from 5 to 530 Oe within the temperature range from 300 to 2 K. Magnetism observed in the films was found to change gradually from ferromagnetic spin ordering to pinned magnetic domain interactions mixed with weak spin-glass-like behavior of magnetically frustrated antiferromagnetic/ferromagnetic (AFM-FM) spin ordering depending on the temperature and magnitude of the applied magnetic field. Antiferromagnetic order of spin cycloids was broken in polycrystalline films by crystal sizes smaller than the cycloid length (∼60 nm). Uncompensated spincycloids and magnetic domain walls were found to be the cause of the high magnetization of the BFO films.

Formation of BiFeO3 from a Binary Oxide Superlattice Grown by Atomic Layer Deposition

“…Although ALD is primarily used for the growth of binary oxide films and coatings, in the last years the integration of epitaxial perovskite thin films on semiconductor substrates has been reported, making this synthesis method appealing for large‐scale deposition of complex functional oxides such as ferroelectric BaTiO 3 or BFO . The synthesis of ferroelectrically switchable BFO utilizing ALD was demonstrated for both epitaxial and polycrystalline films . Direct evidence of ferroelectricity with a remnant polarization of ≈2 μC cm −2 was first reported for a 10‐nm‐thick film grown on a LaNiO 3 (001)/SiO 2 /Si(001) substrate .…”

Synthesis of Zinc - Bismuth Complex Oxide and Experimental Analysis of Its Magnetic and Electrical Characteristics

“…And then we use the silver paint to connect the probe with the sample, so that the probe can be evenly attached to the measured sample with a constant current source from the outermost two current source access current. Then we measure the middle two voltage of the probes, so the resistance value of the sample can be calculated from the voltage and the current, thereby we can obtain the resistivity [2]. Figure 4.…”

“…This is because the ACMS uses a unique detection coil and a drive motor. And through the coil compensation and multi-point measurement, the noise generated inside and ousider the equipment can be eliminated effectively [2] [4]. At the same time, a digital thermometer in the sample cavity near the sample can be used to measure the temperature range from 1.9K-350K.…”

“…They can be applied to many aspects, such as catalysts, electrolyte materials, optoelectronic materials, electronic ceramic powder materials, high temperature superconducting materials. In addition, they can also be applied in other materials such as nuclear waste materials, absorbing materials, in which these complex oxide crystals also have a good application prospects [2] [3]. Therefore, the formation mechanism of dendrites has attracted much attention for a long time, and most of them have been focused on the fractal research.…”

Improved multiferroic properties in (1−x)BiFeO3–xBaTi0.95(Yb0.5Nb0.5)0.05O3 system (0≤x≤0.3)

“… the modulation of spin spiral structure [19,[47][48][49]  the effect of grain size [50][51][52]: with dimension less than 62 nm, the probable modification of cycloid spin structure of BiFeO 3 can lead to weak ferromagnetism, and  the presence of Fe 2+ ions probably leading to a double-exchange interaction between Fe 3+ and Fe 2+ (Fe 3+ -O-Fe 2+ ) influenced magnetization [17,23] Compared to these works, in our system, the enhancement of ferromagnetic properties of BiFeO 3 as a results of doping non-magnetic Ba 2+ and Yb 3+ /Nb 5+/ Ti 4+ in A and B sites, respectively, could be attributed to the contribution of the above mentioned factors.…”