We present the polarization observations toward the circumstellar disk around HD 142527 by using Atacama Large Millimeter/submillimeter Array ( ALMA ) at the frequency of 343 GHz .
The beam size is 0 \farcs 51 \times 0 \farcs 44 , which corresponds to the spatial resolution of \sim 71 \times 62 au .
The polarized intensity displays a ring-like structure with a peak located on the east side with a polarization fraction of P = 3.26 \pm 0.02 \% , which is different from the peak of the continuum emission from the northeast region .
The polarized intensity is significantly weaker at the peak of the continuum where P = 0.220 \pm 0.010 \% .
The polarization vectors are in the radial direction in the main ring of the polarized intensity , while there are two regions outside at the northwest and northeast areas where the vectors are in the azimuthal direction .
If the polarization vectors represent the magnetic field morphology , the polarization vectors indicate the toroidal magnetic field configuration on the main ring and the poloidal fields outside .
On the other hand , the flip of the polarization vectors is predicted by the self-scattering of thermal dust emission due to the change of the direction of thermal radiation flux .
Therefore , we conclude that self-scattering of thermal dust emission plays a major role in producing polarization at millimeter wavelengths in this protoplanetary disk .
Also , this puts a constraint on the maximum grain size to be approximately 150 { \mu m } if we assume compact spherical dust grains .