LAUSR

The low braking-index pulsar PSR J1734$-$3333 could be born with superhigh internal magnetic fields $B_{\rm in}\sim10^{15}-10^{16}$ G, and undergo a supercritical accretion soon after its formation in a supernova explosion. The buried multipole magnetic fields will merger into a dipole magnetic field. Since the magnetic flow transfers from the core to the crust of the pulsar, its surface dipole field grows quickly at a power-law form assumed until it saturates at the level of internal dipole field. The increase in surface dipole magnetic field results in the observed low braking index of $n=0.9(2)$. Keeping an average field growth index $\varepsilon=1.34(6)$, this pulsar will become a magnetar with surface dipole magnetic field at the equator $B_{\rm d}\sim 2.6(1)\times 10^{14}$\,G and $\sim 5.3(2)\times 10^{14}$\,G after next 50\,kyrs and 100\,kys, respectively.