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Unveiling hidden ferrimagnetism and giant magnetoelectricity in polar magnet Fe2Mo3O8.

Wang Y, Pascut GL, Gao B, Tyson TA, Haule K, Kiryukhin V, Cheong SW - Sci Rep (2015)

Bottom Line: Magnetoelectric (ME) effect is recognized for its utility for low-power electronic devices.Largest ME coefficients are often associated with phase transitions in which ferroelectricity is induced by magnetic order.The observed effects are associated with a hidden ferrimagnetic order unveiled by application of a magnetic field.

View Article: PubMed Central - PubMed

Affiliation: Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.

ABSTRACT
Magnetoelectric (ME) effect is recognized for its utility for low-power electronic devices. Largest ME coefficients are often associated with phase transitions in which ferroelectricity is induced by magnetic order. Unfortunately, in these systems, large ME response is revealed only upon elaborate poling procedures. These procedures may become unnecessary in single-polar-domain crystals of polar magnets. Here we report giant ME effects in a polar magnet Fe2Mo3O8 at temperatures as high as 60 K. Polarization jumps of 0.3 μC/cm(2), and repeated mutual control of ferroelectric and magnetic moments with differential ME coefficients on the order of 10(4) ps/m are achieved. Importantly, no electric or magnetic poling is needed, as necessary for applications. The sign of the ME coefficients can be switched by changing the applied "bias" magnetic field. The observed effects are associated with a hidden ferrimagnetic order unveiled by application of a magnetic field.

No MeSH data available.


Related in: MedlinePlus

Magnetoelectric effect, and the associated ionic shifts.(a,b) Magnetic field dependence of magnetization M(H) and polarization P(H) at T = 55 K. Numbers and arrows indicate the measurement sequence. The insert in (b) shows the magnetic orders and the ferrimagnetic moments of the Fe-O layers for the phases involved. (c) The calculated ionic shifts for the paramagnetic to AFM transition. Thick arrow represents the corresponding change of the electric polarization, ΔP. (d) the same as (c), but for the AFM to FRM transition.
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f3: Magnetoelectric effect, and the associated ionic shifts.(a,b) Magnetic field dependence of magnetization M(H) and polarization P(H) at T = 55 K. Numbers and arrows indicate the measurement sequence. The insert in (b) shows the magnetic orders and the ferrimagnetic moments of the Fe-O layers for the phases involved. (c) The calculated ionic shifts for the paramagnetic to AFM transition. Thick arrow represents the corresponding change of the electric polarization, ΔP. (d) the same as (c), but for the AFM to FRM transition.

Mentions: The calculated ionic shifts for the transitions from the paramagnetic (PARA) to the AFM state, and from AFM to FRM, are shown in Figs 1(c) and 3(c,d). The ionic shifts for every ion in the unit cell are given in Supplementary Table I. The experimental paramagnetic structure, and the calculated AFM and FRM structures were used. The ionic shifts can be utilized for an estimate of the magnetically-induced electric polarization change ΔP. While the total polarization is a multivalued quantity, the difference ΔP between two structures is a well-defined quantity34. For a qualitative comparison with experiment, it is sufficient to use the ionic-like formula for ΔP given by , where and are the c-axis ionic coordinates for the initial and the final structures, respectively, are the formal ionic charges, V is the unit cell volume, and the sum is taken over the unit cell. For the PARA to AFM, and AFM to FRM transitions, we obtain ΔP values of 0.60(11) μC/cm2 and −0.55(11) μC/cm2, respectively. The calculated magnitudes and the relative signs of ΔP are in good qualitative agreement with our experiments. The positive sign of ΔP for the PARA to AFM transition indicates that the ΔP vector points along the positive c axis, justifying the convention used in our work.


Unveiling hidden ferrimagnetism and giant magnetoelectricity in polar magnet Fe2Mo3O8.

Wang Y, Pascut GL, Gao B, Tyson TA, Haule K, Kiryukhin V, Cheong SW - Sci Rep (2015)

Magnetoelectric effect, and the associated ionic shifts.(a,b) Magnetic field dependence of magnetization M(H) and polarization P(H) at T = 55 K. Numbers and arrows indicate the measurement sequence. The insert in (b) shows the magnetic orders and the ferrimagnetic moments of the Fe-O layers for the phases involved. (c) The calculated ionic shifts for the paramagnetic to AFM transition. Thick arrow represents the corresponding change of the electric polarization, ΔP. (d) the same as (c), but for the AFM to FRM transition.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508583&req=5

f3: Magnetoelectric effect, and the associated ionic shifts.(a,b) Magnetic field dependence of magnetization M(H) and polarization P(H) at T = 55 K. Numbers and arrows indicate the measurement sequence. The insert in (b) shows the magnetic orders and the ferrimagnetic moments of the Fe-O layers for the phases involved. (c) The calculated ionic shifts for the paramagnetic to AFM transition. Thick arrow represents the corresponding change of the electric polarization, ΔP. (d) the same as (c), but for the AFM to FRM transition.
Mentions: The calculated ionic shifts for the transitions from the paramagnetic (PARA) to the AFM state, and from AFM to FRM, are shown in Figs 1(c) and 3(c,d). The ionic shifts for every ion in the unit cell are given in Supplementary Table I. The experimental paramagnetic structure, and the calculated AFM and FRM structures were used. The ionic shifts can be utilized for an estimate of the magnetically-induced electric polarization change ΔP. While the total polarization is a multivalued quantity, the difference ΔP between two structures is a well-defined quantity34. For a qualitative comparison with experiment, it is sufficient to use the ionic-like formula for ΔP given by , where and are the c-axis ionic coordinates for the initial and the final structures, respectively, are the formal ionic charges, V is the unit cell volume, and the sum is taken over the unit cell. For the PARA to AFM, and AFM to FRM transitions, we obtain ΔP values of 0.60(11) μC/cm2 and −0.55(11) μC/cm2, respectively. The calculated magnitudes and the relative signs of ΔP are in good qualitative agreement with our experiments. The positive sign of ΔP for the PARA to AFM transition indicates that the ΔP vector points along the positive c axis, justifying the convention used in our work.

Bottom Line: Magnetoelectric (ME) effect is recognized for its utility for low-power electronic devices.Largest ME coefficients are often associated with phase transitions in which ferroelectricity is induced by magnetic order.The observed effects are associated with a hidden ferrimagnetic order unveiled by application of a magnetic field.

View Article: PubMed Central - PubMed

Affiliation: Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.

ABSTRACT
Magnetoelectric (ME) effect is recognized for its utility for low-power electronic devices. Largest ME coefficients are often associated with phase transitions in which ferroelectricity is induced by magnetic order. Unfortunately, in these systems, large ME response is revealed only upon elaborate poling procedures. These procedures may become unnecessary in single-polar-domain crystals of polar magnets. Here we report giant ME effects in a polar magnet Fe2Mo3O8 at temperatures as high as 60 K. Polarization jumps of 0.3 μC/cm(2), and repeated mutual control of ferroelectric and magnetic moments with differential ME coefficients on the order of 10(4) ps/m are achieved. Importantly, no electric or magnetic poling is needed, as necessary for applications. The sign of the ME coefficients can be switched by changing the applied "bias" magnetic field. The observed effects are associated with a hidden ferrimagnetic order unveiled by application of a magnetic field.

No MeSH data available.


Related in: MedlinePlus