Switching from pyroelectric to ferroelectric order in Ni doped CaBaCo4O7

Abstract

We report ferroelectric ordering in Ni substituted CaBaCo4O7. Magnetization showed ferrimagnetic transition at 60 K and an additional transition is found ~ 82 K, further, enhanced antiferromagnetic interactions and decrease in saturation magnetization are noticed with Ni substitution. The dielectric and pyroelectric measurements illustrate a strong coupling between spin and charge degrees of freedom; ferroelectric behavior is confirmed with enhanced ordering temperature (~82 K) and saturation polarization (250 muC/m2. Neutron diffraction has revealed an increase in c-lattice parameter in Ni sample and all the Co/Ni moments are reoriented in a- direction; evidently a non-collinear ferrimagnetic to collinear ferrimagnetic spin order is observed. The coupling between the triangular and Kagome layers weakens and leads to up-up-down-down AFM ordering in the Kagoma layer. This can be viewed as a 2D-collinear layer with unequal bond distances and most likely responsible for the switching of electric polarization.

arXiv comment19 pages

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Cited by in corpus (5)

• Enhancement of giant magnetoelectric effect in Ni-doped CaBaCo${}_4$O${}_7$
• Remarkable effects of dopant valency $-$ a comparative study of CaBaCo${}_{3.96}$Cr${}_{0.04}$O${}_7$ and CaBaCo${}_{3.96}$Ni${}_{0.04}$O${}_7$
• Structural, magnetic and electric polarization properties of geometrically frustrated YBaCo4O7 and DyBaCo4O7 cobaltites
• Magnetoelectric Effect Dependent on Electric Field Direction in a Pyroelectric Ferrimagnet CaBaCo${}_4$O${}_7$
• Coexistence of magnetic and dielectric glassy states in alternating kagome and triangular lattice LuBaCo${}_4$O${}_7$ cobaltite