Do you want to publish a course? Click here

Electric field control of magnetic phase transitions in Ni3V2O8

204   0   0.0 ( 0 )
 Added by Gavin Lawes
 Publication date 2007
  fields Physics
and research's language is English




Ask ChatGPT about the research

We report on the electric field control of magnetic phase transition temperatures in multiferroic Ni3V2O8 thin films. Using magnetization measurements, we find that the phase transition temperature to the canted antiferromagnetic state is suppressed by 0.2 K in an electric field of 30 MV/m, as compared to the unbiased sample. Dielectric measurements show that the transition temperature into the magnetic state associated with ferroelectric order increases by 0.2 K when the sample is biased at 25 MV/m. This electric field control of the magnetic transitions can be qualitatively understood using a mean field model incorporating a tri-linear coupling between the magnetic order parameters and spontaneous polarization.



rate research

Read More

311 - M. Nardone , V. G. Karpov 2011
We show that strong enough electric fields can trigger nucleation of needle-shaped metallic embryos in insulators, even when the metal phase is energetically unfavorable without the field. This general phenomenon is due to the gigantic induced dipole moments acquired by the embryos which cause sufficient electrostatic energy gain. Nucleation kinetics are exponentially accelerated by the field-induced suppression of nucleation barriers. Our theory opens the venue of field driven material synthesis. In particular, we briefly discuss synthesis of metallic hydrogen at standard pressure.
222 - A. K. Singh , D. Jain , V. Ganesan 2009
The geometrically frustrated magnet Ni3V2O8 undergoes a series of competing magnetic ordering at low temperatures. Most importantly, one of the incommensurate phases has been reported to develop a ferroelectric correlation caused by spin frustration. Here we report an extensive thermodynamic, dielectric and magnetic study on clean polycrystalline samples of this novel multiferroic compound. Our low temperature specific heat data at high fields up to 14 Tesla clearly identify the development of a new magnetic field induced phase transition below 2 K that shows signatures of simultaneous electric ordering. We also report temperature and field dependent dielectric constant that enables us to quantitatively estimate the strength of magneto-electric coupling in this improper ferroelectric material.
Neutron diffraction is used to probe the (H,T) phase diagram of magneto-electric (ME) LiNiPO4 for magnetic fields along the c-axis. At zero field the Ni spins order in two antiferromagnetic phases. One has commensurate (C) structures and general ordering vectors (0,0,0), the other one is incommensurate (IC) with ordering vector (0,q,0). At low temperatures the C order collapses above 12 Tesla and adopts an IC structure with modulation vector parallel to (0,q,0). We show that C order is required for the ME effect and establish how electric polarization results from a field-induced reduction of the total magneto-elastic energy.
263 - P. J. Ryan , J. -W. Kim , T. Birol 2012
Intrinsic magnetoelectric coupling describes the interaction between magnetic and electric polarization through an inherent microscopic mechanism in a single phase material. This phenomenon has the potential to control the magnetic state of a material with an electric field, an enticing prospect for device engineering. We demonstrate giant magnetoelectric cross-field control in a single phase rare earth titanate film. In bulk form, EuTiO3 is antiferromagnetic. However, both anti and ferromagnetic interactions coexist between different nearest neighbor europium ions. In thin epitaxial films, strain can be used to alter the relative strength of the magnetic exchange constants. Here, we not only show that moderate biaxial compression precipitates local magnetic competition, but also demonstrate that the application of an electric field at this strain state, switches the magnetic ground state. Using first principles density functional theory, we resolve the underlying microscopic mechanism resulting in the EuTiO3 G-type magnetic structure and illustrate how it is responsible for the giant cross-field magnetoelectric effect.
We present the microscopic theory of improper multiferroicity in BiMnO3, which can be summarized as follows: (1) the ferroelectric polarization is driven by the hidden antiferromagnetic order in the otherwise centrosymmetric C2/c structure; (2) the relativistic spin-orbit interaction is responsible for the canted spin ferromagnetism. Our analysis is supported by numerical calculations of electronic polarization using Berrys phase formalism, which was applied to the low-energy model of BiMnO3 derived from the first-principles calculations. We explicitly show how the electric polarization can be controlled by the magnetic field and argue that BiMnO3 is a rare and potentially interesting material where ferroelectricity can indeed coexist and interplay with the ferromagnetism.
comments
Fetching comments Fetching comments
Sign in to be able to follow your search criteria
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا