We present neutron diffraction data for the cubic-heavy-fermion YbBiPt that show broad magnetic diffraction peaks due to the fragile short-range antiferromagnetic (AFM) order persist under an applied magnetic-field $mathbf{H}$. Our results for $mathbf{H}perp[bar{1}~1~0]$ and a temperature of $T=0.14(1)$ K show that the $(frac{1}{2},frac{1}{2},frac{3}{2})$ magnetic diffraction peak can be described by the same two-peak lineshape found for $mu_{0}H=0$ T below the N{e}el temperature of $T_{text{N}}=0.4$ K. Both components of the peak exist for $mu_{0}Hlesssim1.4 T$, which is well past the AFM phase boundary determined from our new resistivity data. Using neutron diffraction data taken at $T=0.13(2)$ K for $mathbf{H}parallel[0~0~1]$ or $[1~1~0]$, we show that domains of short-range AFM order change size throughout the previously determined AFM and non-Fermi liquid regions of the phase diagram, and that the appearance of a magnetic diffraction peak at $(frac{1}{2},frac{1}{2},frac{1}{2})$ at $mu_{0}Happrox0.4$ T signals canting of the ordered magnetic moment away from $[1~1~1]$. The continued broadness of the magnetic diffraction peaks under a magnetic field and their persistence across the AFM phase boundary established by detailed transport and thermodynamic experiments present an interesting quandary concerning the nature of YbBiPts electronic ground state.
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