Optical Magnetoelectric Effect in the PolarGaFeO3Ferrimagnet

Abstract

The optical magnetoelectric (ME) effect, i.e., the change of optical absorption upon the reversal of the light propagation direction, has been investigated for a polar ferrimagnet GaFeO3. For dipole- and spin-forbidden d-d transition bands located at 1.2-2.3 eV, a clear signal of the optical ME effect (Deltaalphat approximately 3x10(-3)) is observed with an applied magnetic field as low as 500 Oe and a sample thickness (t) of 50 microm. The observation of a large ME effect in the present compound suggests a possible route to magnification of this novel phenomenon for application.

Gigantic Optical Magnetoelectric Effect in CuB2O4

“…5,6) This type of OME effect was reported in GaFeO 3 , in which P s and M s are along the b and c axes, respectively. [5][6][7] The group theory predicts the existence of the bc and cb terms of linear ME tensor . Electromagnetic wave propagating along the a axis consists of electric field E .…”

“…4) In materials with spontaneous magnetization M s and polarization P s , a similar nonreciprocal effect, termed optical magneto-electric (OME) effect hereafter, arises when light propagates in the P s  M s direction. 5,6) This type of OME effect was reported in GaFeO 3 , in which P s and M s are along the b and c axes, respectively.5-7) The group theory predicts the existence of the bc and cb terms of linear ME tensor . Electromagnetic wave propagating along the a axis consists of electric field E !…”

“…1,2) One of the intriguing effects in such ME materials is a peculiar nonreciprocal optical effect, which is a change in optical constants with the reversal of propagating direction of light. [3][4][5][6] This effect can be regarded as an expansion of linear ME effects into optical frequencies. The nonreciprocal optical effect in ME materials is classified according to the type of the light polarization.…”

Structural, magnetic and vibrational properties of multiferroic GaFeO3 at high pressure

“…These compounds exhibit a ferrimagnetic order and the magnetic ordering temperature T N can be tuned in wide limits around ambient temperature (200 -340 K) depending on chemical composition and synthesis procedure. Their unique magnetoelectric [6], magneto-optic [7] and piezoelectric [8,9] properties are also important for understanding fundamental nature of multiferroicity. At temperatures below T N Ga 2-x Fe x O 3 shows a relatively strong magnetoelectric coupling [9,10].…”

Multiferroic TbMnO3 nanoparticles

“…These materials are being studied either in the form of intrinsic systems involving single phase multiferroic crystalline compounds or in the form of artificially engineered nanostructures comprising of individually non-multiferroic ferromagnetic and ferroelectric components [2], [3], [4], [5], [6], [7], [8], [9], [10] and [11]. Although the recent research on single crystal intrinsic multiferroics has brought out many new phenomena in these materials, these mainly occur at very low temperatures [5], [7], [8], [9], [10] and [11]. Unfortunately, the magneto-electric coupling effects in nanoengineered composites have also been rather weak at practical temperatures [4] and [6].…”