Multiple magnetic transitions in SmCoAsO

Abstract

The magnetic properties of SmCoAsO have been investigated. Our results differ from early observations. Complicated magnetism consists of antiferromagnetic, ferromagnetic, ferrimagnetic and paramagnetic, even diamagnetism at low field has been observed. A metamagnetic transition was observed, resulting from a canting of the spins. The interaction between two Co sublattices with canted-structure might take responsibility for the multiple magnetic transitions. Electrical resistivity data indicate that SmCoAsO is metallic conductor with room temperature resistivity of 0.51669 mΩ-cm. Negative magnetoresistance effect suggests a significant suppression of spin-flip scattering by the applied magnetic field. The magnetic phase diagram has been established

The resonant, near-resonant, and off-resonant plasmon coupling effects for the bonding modes in two types of asymmetric dimer

“…It is noteworthy that the dark modes can be excited in the asymmetric nanoantenna under asymmetric excitation of light due to symmetry breaking [27]. The other important configuration of heterodimers is formed by different compositions regardless of the sizes and shapes [10,11,[22][23][24][25]. The redshift of the coupled modes under longitudinal polarization with decreasing gap has been found in Ag-Cu heterodimers and Ag-Au heterodimers [11,22,24].…”

“…The other important configuration of heterodimers is formed by different compositions regardless of the sizes and shapes [10,11,[22][23][24][25]. The redshift of the coupled modes under longitudinal polarization with decreasing gap has been found in Ag-Cu heterodimers and Ag-Au heterodimers [11,22,24]. The dark modes also emerge due to the incomplete cancellation of the nonequivalent dipole moments from different monomers [22].…”

“…One of the usual coupling effects is the peak-shift behaviour. For instance, there is a redshift behaviour of the coupled modes in silver or gold nanoparticle homodimers with decreasing separation distance (gap) when the polarization of the light is along the interparticle axis of the dimers (longitudinal polarization) [6,[11][12][13][14][15]. In contrast, there is a blueshift behaviour with decreasing gap if the polarization of light is perpendicular to the interparticle axis of the dimers (transverse polarization) [14,15].…”

“…Meanwhile, the dipole oscillator model arising from the collective motion of surface charges of metallic nanoparticles can also be used to understand qualitatively the plasmonic phenomena [21], and then the dipolar-quasistatic approximation also works well [22,23]. Recently, the asymmetrical coupling of plasmon modes has become a more interesting topic [10][11][12][22][23][24][25][26][27]. One configuration for asymmetry in the dimers is formed by monomers with different sizes and/or shapes but the same composition [12,26,27].…”

“…The dark modes also emerge due to the incomplete cancellation of the nonequivalent dipole moments from different monomers [22]. The hybridization models can be used to explain those phenomena [11,22,26]. However, for understanding the redshift of coupled modes on the high frequency side, the quasi-continuum of interband transitions is introduced in the hybridization model [11,22].…”